This 4 of a high-quality leaf Polyurethane spring kit is perfect for your Peterbilt truck. It includes a 4" wide spring, housing, and bushing for optimal performance. The kit is designed to fit perfectly with your truck and is made from durable materials to ensure long-lasting use. With interchange part numbers including 03-01654, 338-1224, E321-75, 334-460, 03-01657, 361-161, 338-725, E697-75, and 03AL1, you can be sure that this kit will work with your specific model. The manufacturer part numbers are 0301661, 03-01654, 338-1224, E321-75, 334-460, 2312734120, 03-01657, 361-161, 338-725, 0305915, E697-75, and 03AL1. The included hardware is 4 of ATRO Polyurethane bushing, bushing housing , top plate and U-bolt with washer and nuts.This leaf spring kit is perfect for anyone looking to improve the performance of their Peterbilt truck's suspension system. Get yours today and enjoy a smoother ride and improved handling.