Size: Diameter 5/16 inch, Length 1-1/4 inch-18 pitch. Crafted from high-quality low carbon steel and coated with a durable galvanization finish, these carriage bolts offer exceptional strength and resistance to rust. Unlike standard steel bolts, they maintain their integrity in extreme temperature environments, ensuring reliable performance without the risk of thread damage or biting issues. This comprehensive kit includes bolts, lock nuts, and flat washers, conveniently packaged together for ease of use. The nylon insert hex lock nut provides superior clamping force, reducing the likelihood of loosening over time, while the large flat washer is designed to withstand harsher working conditions. The unique square neck beneath the round head ensures a secure fit in square holes, promoting self-locking capabilities during installation. This assortment adheres to ANSI standards and has undergone rigorous quality control tests to guarantee reliability and performance. Please review the product specifications and installation requirements carefully to ensure compatibility with your project. Our dedicated customer service team is available to assist with any inquiries, ensuring a smooth installation experience. Product Description High-quality low carbon steel construction for enhanced durability. Galvanized finish provides excellent rust resistance. Includes lock nuts and flat washers for a complete installation solution. Square neck design for secure locking in square holes. Meets ANSI standards and undergoes rigorous quality control testing.