Supreme Suspensions - Silverado Shock Extenders High-Strength Carbon Steel Shock Extension Kit (Black) Easy Install Silverado Shock Extension PRO CONTENTS: 2x Carbon Steel Shock Extenders, Installation Hardware, Installation Instructions and Pro Pack. FITMENTS: Chevy Silverado 1500 2007-2015 2WD 4WD; GMC Sierra 1500 2007-2015 2WD 4WD TECHNICAL NOTES: Maintains factory ride quality. For models with 6-lug axle configurations. BENEFITS: Reduces over-extending shock pistons so that you can use your factory shocks without replacements. INSTALLATION: Installation takes 1 - 2 hours. No special tools are required.