Discover Our Precision Pins: Slotted Spring Pins, Trailer Pins, Pivot Pins, and Dowel Pins | Zhejiang Zhongrui Auto Parts | Engineered for Secure and Reliable Connections Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Slotted Spring Pins: Versatile pins providing flexible fastening solutions, absorbing shock and vibration. Trailer Pins: Robust pins designed for secure trailer connections, ensuring safety and reliability. Pivot Pins: Essential for hinge and pivot applications, providing smooth and durable movement. Dowel Pins: Precision-made pins for accurate alignment and secure positioning in various assemblies. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Automotive Trailers & Towing Machinery & Equipment General Assembly And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Secure Your Connections with Our Precision Nuts: Wheel Nuts, Cap Nuts, Weld Nuts, and Slotted Nuts | Zhejiang Zhongrui Auto Parts | Engineered for Reliability and Performance Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Wheel Nuts: Designed for secure wheel attachment in automotive applications, ensuring safety and stability. Cap Nuts: Providing a clean, finished look while protecting threads from damage and corrosion. Weld Nuts: Offering a strong, permanent fastening solution for sheet metal and various industrial applications. Slotted Nuts: Ideal for locking applications with cotter pins, preventing loosening in high-vibration environments. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Bolt Property Class: 8.8, 10.9, 12.9 (specialized) Metric Thread Sizes: M3 to M64 Nut Thread Class: 6H, 7H (Ensures proper thread fit) Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Automotive Industrial Machinery Construction General Assembly And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Explore Our Essential Plugs: Industrial Plugs, Oil Drain Plugs, Oil Temperature Gauge Fittings, and Self-Locking Plugs | Zhejiang Zhongrui Auto Parts | Ensuring Secure and Reliable Connections Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Industrial Plugs: Versatile plugs designed for various industrial applications, providing reliable sealing and closure solutions. Oil Drain Plugs: Essential for oil maintenance, ensuring secure and leak-free drainage of fluids. Oil Temperature Gauge Fittings: Designed for accurate temperature monitoring, providing reliable connections for oil temperature gauges. Self-Locking Plugs: Engineered with self-locking mechanisms, preventing loosening and ensuring secure connections in critical applications. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Bolt Property Class: 8.8, 10.9, 12.9 (specialized) Metric Thread Sizes: M3 to M64 Nut Thread Class: 6H, 7H (Ensures proper thread fit) Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Industrial Machinery Automotive Fluid Systems Maintenance and Repair And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Discover Our Diverse Range: Industrial Screws, Hex Socket Screws, Planetary Gear Shaft Set Screws, and Grub Screws | Zhejiang Zhongrui Auto Parts | Precision and Reliability in Every Fastener Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Industrial Screws: Versatile screws designed for a wide range of industrial applications, providing reliable fastening solutions. Hex Socket Screws: Ideal for applications requiring high torque and secure fastening with an internal hex drive. Planetary Gear Shaft Set Screws: Specifically designed for use in planetary gear systems, ensuring precise alignment and secure locking. Grub Screws: Commonly used for securing components in place, preventing movement or loosening. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Bolt Property Class: 8.8, 10.9, 12.9 （specialized） Metric Thread Sizes: M3 to M64 Nut Thread Class: 6H, 7H (Ensures proper thread fit) Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Industrial Machinery Automotive Gear Systems General Assembly And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Discover Our High-Precision Security Screws, Square Head Set Screws with Cup Point, Counterweight Screws, and Set Screws | Zhejiang Zhongrui Auto Parts | Engineered for Reliability Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Security Screws: Designed for tamper-proof applications, providing enhanced security and preventing unauthorized access. Square Head Set Screws with Cup Point: Ideal for secure fastening with a square head for high torque applications and a cup point for reliable locking. Counterweight Screws: Specifically engineered for use in counterweight systems, ensuring precise balance and stability. Set Screws: Versatile fasteners used for securing components in various assemblies, preventing movement or loosening. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Machinery Automotive Industrial Equipment Security Systems And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Product Definition: High-strength connection components ensuring secure coupling between towing vehicles and trailers. Trailer hitch pins are integral to heavy-duty towing applications, acting as the vital link between towing vehicles and trailers. Their primary function is to provide a secure and reliable connection, transferring the towing force while ensuring the stability and safety of the coupled vehicles. These pins are typically forged from high-strength alloy steels, such as 42CrMo4, to endure the extreme shear and torsional stresses encountered during towing. Precision in manufacturing is crucial, with controlled heat treatment processes achieving optimal core and surface hardness. Surface coatings, such as hot-dip galvanizing or Dacromet, are applied to combat corrosion in harsh environmental conditions. The reliability of trailer hitch pins is paramount for preventing catastrophic failures during towing. Any deviation from specified tolerances or material properties can lead to compromised connection integrity, posing significant safety risks. Therefore, rigorous quality control, adherence to industry standards (e.g., SAE, DIN, ISO), and comprehensive load testing are indispensable throughout the production process. Beyond standard applications in logistics and agricultural towing, these pins are also essential in recreational vehicle (RV) installations and marine trailer setups. Customization options, including adjustable lengths, varied diameters, and specialized thread patterns, allow for seamless integration with diverse towing systems and equipment. Technical Breakdown: Trailer hitch pins serve as the critical safety interface in towing systems, engineered to maintain structural integrity under dynamic loads. These components undergo rigorous testing to withstand: Shear forces up to 12,000 lbs (DIN 14889-1)Torsional stresses from uneven road surfacesCorrosive environments (salt spray resistance 500h per ASTM B117) Manufactured from 42CrMo4 alloy steel (EN 10083-1) through closed-die forging processes, our pins achieve:  Core hardness: 38-42 HRC  Surface hardness: 45-50 HRC via induction hardening  Fatigue resistance: 1×10⁷ cycles at 75% ultimate tensile strength Available in multiple configurations:  Class III-V hitches (SAE J684 compliant)  Adjustable length designs (200-600mm range)  Safety lock variants with dual retention mechanisms Application Scenarios:  Agricultural equipment towing  Logistics semi-trailer connections  RV fifth-wheel installations  Marine trailer applications We share daily update in our Insightful NEWSLETTER!Learn more and Contact us   Click Drop us a messageto get the latest catalog and quotation Linkedin Page   •    Products    •    Meet us at exhibition    •    Drop us a message 

Discover Our Precision-Engineered Thrust Bolts, Planetary Carrier Mounting Bolts, and Stud Bolts | Zhejiang Zhongrui Auto Parts | High-Performance Fastening Solutions Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Thrust Bolts: Designed to withstand axial loads, ensuring reliable performance in demanding applications.Planetary Carrier Mounting Bolts: Ideal for securing planetary carriers in gear systems, providing robust and precise connections.Stud Bolts: Versatile fasteners with threaded ends, suitable for various assembly applications.Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required.Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required.Customization: OEM & ODM services available for tailored solutions.Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers.Certifications: IATF 16949Standards: DIN, GB, ANSI, BSW, ISOPackaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand.Delivery: Sample stock and strong production capacity ensure timely delivery. Applications:AutomotiveHeavy-Duty MachineryIndustrial EquipmentTransmission SystemsAnd more! Contact us to learn more about our fastening solutions and get a quotation:www.zjzrqc.comDirector of Business Development Coco Chen: coco.chen@zjzrap.comAccount Manager Grace Gan: grace.gan@zjzrap.comAccount Manager Freddie Xiao: freddie.xiao@zjzrap.com

Discover Our Robust Track Bolts, Hex Head Drilled Bolts, Hex Flange Bolts, and Wheel Bolts | Zhejiang Zhongrui Auto Parts | Precision Engineered Fasteners Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Track Bolts: Designed for heavy-duty applications, ensuring secure connections in track systems. Hex Head Drilled Bolts: Ideal for applications requiring locking mechanisms with cotter pins or wire. Hex Flange Bolts: Provide secure fastening with an integrated flange for enhanced load distribution. Wheel Bolts: Engineered for reliable wheel mounting in automotive and industrial vehicles. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Standards: DIN, GB, ANSI, BSW, ISO Certifications: IATF 16949 Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Automotive Industrial Machinery Construction Heavy Equipment Railway And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Explore Our High-Performance Axle Housing Wheel Rim Bolts, Axle Housing Flange Bolts, Ball Head Bolts, and Drive Shaft Locking Bolts | Zhejiang Zhongrui Auto Parts | Precision Engineered Fasteners Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products: (See Images Attached!) Axle Housing Wheel Rim Bolts: Designed for secure wheel mounting on axle housings, ensuring reliable performance. Axle Housing Flange Bolts: Ideal for connecting flanges on axle housings, providing robust and leak-proof connections. Ball Head Bolts: Versatile fasteners with a spherical head, suitable for various mechanical applications. Drive Shaft Locking Bolts: Engineered for secure locking of drive shaft components, preventing loosening under stress. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Standards: DIN, GB, ANSI, BSW, ISO Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Sample stock and strong production capacity ensure timely delivery. Applications: Automotive Heavy-Duty Trucks Industrial Machinery Agricultural Equipment And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Partner with the Experts: Zhejiang Zhongrui Auto Parts at the 2025 China Yiwu International Auto And Motorcycle Expo! About Us: For over 38 years, Zhejiang Zhongrui Auto Parts Co., Ltd. has been a leading manufacturer of high-quality fasteners, serving the automotive, industrial, and agricultural sectors. Our state-of-the-art 20,000+ square meter factory, equipped with advanced multi-station cold heading and hot forging machinery, ensures precision and reliability in every product. With a catalog of over 10,000 specifications, we offer a comprehensive range of standard and custom fastening solutions. Our commitment to quality is backed by IATF 16949 certification and rigorous testing procedures, including tensile testing, salt spray testing, and dimensional inspections. Why Choose Zhongrui? Expertise & Experience: Over 38 years of industry leadership. Advanced Manufacturing: Multi-station cold heading and hot forging processes. Custom Solutions: Tailored fasteners to meet your specific needs. Superior Quality: IATF 16949 certified and rigorously tested products. Comprehensive Range: High-strength bolts, nuts, washers, and more. Enhanced Durability: Surface treatments including Dacromet, galvanizing, and more. Visit Us at the 2025 China Yiwu International Auto And Motorcycle Expo! Join us from April 7th-9th at the Yiwu International Expo Center to discover how our fastening solutions can empower your business. Booth E1G13 Contact Us: Website: https://www.zjzrqc.com/ Address: No. 680, Ya'ao Road, Daqiao Town, Nanhu District, Jiaxing City, Zhejiang Province, China General Inquiries: +86-18858333555, zrqiche@163.com Director of Business Development: Coco Chen - coco.chen@zjzrap.com Account Manager: Grace Gan - grace.gan@zjzrap.com Account Manager: Freddie Xiao - freddie.xiao@zjzrap.com

Discover High-Quality Flat Washers, Idler Spacers, Square Taper Washers, and Vibration Dampening Bushings | Zhejiang Zhongrui Auto Parts | Precision Engineered Fasteners Zhejiang Zhongrui Auto Parts brings over 38 years of expertise to the fastener industry, offering a diverse range of precision-engineered components. With a state-of-the-art 20,000+ square meter factory and a catalog of over 10,000 specifications, we are equipped to meet your exact requirements. Featured Products Flat Washers: Essential for load distribution and preventing loosening in various applications. Idler Spacers: Designed to maintain precise spacing and alignment in idler mechanisms. Square Taper Washers: Ideal for structural applications, providing support and stability on angled surfaces. Vibration Dampening Bushings: Reduce noise and vibration, enhancing the performance and longevity of your equipment. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Ample stock and strong production capacity ensure timely delivery. Applications: Automotive Industrial Machinery Construction Heavy Equipment And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com

Discover Our High-Performance Large Bevel Gear Mounting Bolts, Battery J-Bolts, Hinge Bolts, and Tie Rods | Zhejiang Zhongrui Auto Parts | Precision Engineered Fasteners Zhejiang Zhongrui Auto Parts leverages over 38 years of industry expertise to deliver top-tier, precision-engineered fasteners. Our expansive 20,000+ square meter facility and comprehensive catalog of 10,000+ specifications ensure we meet your exact requirements with unmatched quality and efficiency. Featured Products: (See Images Attached!) Large Bevel Gear Mounting Bolts: Designed for robust and secure gear installations in heavy-duty machinery. Battery J-Bolts: Essential for safely securing batteries in automotive and industrial applications. Hinge Bolts: Ideal for creating strong, reliable pivot points in various mechanical assemblies. Tie Rods: Provide critical support and stability in structural and mechanical systems. Key Features: Material: Carbon Steel, Alloy Steel, Stainless Steel, Brass, or as OEM required. Finish: Plain, Zinc Plated (Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G, or as required. Customization: OEM & ODM services available for tailored solutions. Quality Assurance: Rigorous testing with Calipers, Go & No-Go Gauges, Tensile Test Machines, and Salt Spraying Testers. Certifications: IATF 16949 Packaging: 100-1000 PCS per bag with label, export standard carton, or as per customer demand. Delivery: Ample stock and strong production capacity ensure timely delivery. Applications: Automotive Industrial Machinery Construction Heavy Equipment Power Transmission And more! Contact us to learn more about our fastening solutions and get a quotation: www.zjzrqc.com Director of Business Development Coco Chen: coco.chen@zjzrap.com Account Manager Grace Gan: grace.gan@zjzrap.com Account Manager Freddie Xiao: freddie.xiao@zjzrap.com