Digressive piston for automotive suspension dampers: a machined disc in a bright metal finish with a raised central hub and bore, two rings of drilled through-holes across its face and a groove around the outer rim. In a damper, oil flows through the piston's ports, and the digressive design shapes how the damping force builds. It comes from a range of critical components, including air fork products, suspension components and pistons, engineered to withstand harsh conditions in demanding environments. Materials offered: aluminium, brass, SS, MS and plastic.