Moto-Master 4-Piston Supermoto Racing Caliper This caliper is developed specifically for supermoto racing, but also works great for aggressive stunt riding. Moto-Master components are manufactured to the tightest tolerances. This caliper is specially modified to work on the DR-Z 400SM factory supermoto model with this specific Caliper Adapter. It does NOT fit the DRZ E, K, or S models. For use with a 320x5mm rotor (or thicker), not the original 310mm rotor that comes on the DR-Z400SM. The 4-Piston SM Racing Caliper is CNC-machined and anodized black. Uses 4x 27mm stainless steel pistons. It can be used with your stock master cylinder, though a soft lever feel is typical. For the best performance and lever feel, match this caliper with a Moto-Master 12mm Radial Master Cylinder. Each caliper includes a set of SinterPro RacingGP brake pads.