2011-2018 Chevy Silverado, GMC Sierra 2500 HD (Models w/ 1-3" Rear Lift) Dirt Series 2.0 w/ Reservoir Rear Shock by CST Suspension CST Dirt Series 2.0 Reservoir Shocks are perfect for the enthusiast with a lifted truck that likes to push it to the limit. CST Dirt Series Shocks are rebuildable and use urethane bushings for direct fitment and reduced noise vs heim style shocks. Each CST Dirt Series shock is USA made and features vehicle specific valving for optimum performance The part number for this item is CSR-6523 and it fits 2011-2018 Chevy Silverado, GMC Sierra 2500 HD (Models w/ 1-3" Rear Lift).