The new Aero4-ST Quick-Silver forged four piston caliper delivers heavy duty stopping power for the road or track. The caliper incorporates race technology into a body design with widespread adaptability. Radial mounting, multiple options for piston volume, and a rotor diameter ranging from 12.88" to 15.00" give this caliper the versatility necessary to suit all types of heavy weight braking requirements. The new Aero4 is the latest innovation to the W4A / W6A series of calipers. It has been redesigned with internal fluid ports that eliminate the external fluid cross-over tubes and massive center bridge assembly. Equipped with Thermlock piston technology and Wilwood’s Quick-Silver Nickel coating. QS-ST calipers utilizing the new .80” thick 6620 pad plate, give extra pad life for high heat endurance racing