2005-2007 Superduty 8in Front Dirt Logic 4.0 Reservoir Coilover (FABFTS835012)This Dirt Logic 4. 0 coilover shock delivers maximum damping capacity for extreme offroad use while maintaining refined highway ride quality. Designed for full size vehicles that demand the largest and most capable bolt on coilover available, it combines massive internal components with adjustable coilover construction for uncompromising performance. Features 4. 0 inch outer diameter stainless steel shock body for maximum strength and heat dissipation