These high-quality U-Bolts were specifically made for use with Carli's rear block kits on new model Ram 3500 trucks with single rear wheel axles. Each U-Bolt was precision made for a perfect fit and are designed to be used with 1" lift blocks. This kit includes (4) 4.25" Carli U-Bolts and all of the hardware needed for installation. Carli Lift Blocks: This kit will require the Carli 1" Rear Lift Blocks for proper fitment. Vehicle Fitment: 2019, 2020, 2021, 2022, 2023 Dodge Ram 3500 4x4 SRW with 4.25" Axle Tube