ReadyLift 26-3205 5'' Rear Block Kit - Gm Silverado/Sierra 2500HD/3500HD 2011-2018, 1 Pack GM 2500HD/3500HD OEM Style 5" Rear Lift Block Kit 5" Tall rear block kit Cast Iron construction, made in USA E-coated finish Includes new longer U-bolts and hardware, will require longer shocks if you don't already have them.