These Wilwood Dynalite series brake calipers are compact, powerful, and lightweight. They feature a strong compact aluminum-alloy housing, stainless steel deep-cup pistons to reduce heat transfer from your pads to your brake fluid, and high-temperature square piston seals to control piston retraction. Pistons - Count: 4 - Area (in²): 4.12 - Type: Stainless - Dust Boot: No Rotor Dimensions - Rotor Width(In): 0.81 - Rotor Diameter(In): 13.06 Pad Dimensions - Pad Area (in²): 6.36 - Pad Volume (in³): 2.1 Mounting - Mount Center(In): 5.25 - Mount Type: Lug -Mount Side: Universal Duty Rating & Material - Material: Aluminium - Weight(Lbs): 3.3 Colors & Finishes - Color: Polished - Finish: Polish