Features: Pair Hydraulic Disc Brake Caliper Pistons set for mountain road bike brake repairing, fixing Made of high quality material provides great heat resistance effect which can resistant 400 degrees Celsius High performance, very stable, unbreakable and no tearing even after extreme and continuous Fan shaped heat sink design increases air to promote heat dissipation Compatible with BRAKE M640 M810 M820 M7120 M8120 M9120 Disc Brakes Specification: The diameter of the large piston is about 17.2MM, the height is 8.8MM, the diameter of the small piston is about 15.12, and the height is 8.8MM. TYPE: A Material: Phenolic Resin colour: black Package Contents: 2 x large pistons 2 x small pistons 9 x sealing rings Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.