Made from quality light weight high tensile strength aluminum 6061-T6 for great durability. High concentration suspension oil is used for better cushioning force. L-shape piggy with built-in piston spring can adjust the rebound force for better pressure load effect. The coil is thickened from 1.8mm to 2mm to provide more power (can be replaced by original stock spring if softer spring is needed). Damper shaft is thickened from 3.5mm to 5mm to increase sturdiness and prevent bending. Mid-point distance : Front - 135mm (both spring & internal dampers) ; Rear - Spring damper 139mm, Internal Damper 160mm. Package includes : Front + Rear spring dampers-4pcs ; Front + Rear internal dampers-4pcs. Original stock part number : (8450, 8450X, 8450R) + (8451, 8451X, 8451R) + (8460, 8460X, 8460R) + (8461, 8461X, 8461R). Will fit : Traxxas 1/7 Unlimited Desert Racer Pro-Scale 4X4-85076-4 Aluminum 6061-T6 Front + Rear L-Shape Piggy Back (Built-In Piston) Damper Set For Traxxas 1:7 Unlimited Desert Racer UDR Pro-Scale 4X4 (#85076-4) Upgrades - Orange