Factory Connection Progressive Shock Spring - White Power 5018 Shock 8.0-10.3KG/MM , Color: White FCW-3 Progressively wound spring gives a nice, plush ride over the little stuff and wont bottom out over the big stuff The more its compressed, the greater the resistance Cold-wound on precision CNC equipment for the ultimate in strength Heat-tempered, shot-peened and end-ground for durability Preset for fatigue resistance