The BlueSpot Disc Brake Piston Spreader is designed for the separation of brake caliper pistons for the installation of new brake pads. The design ensures the pistons are retracted and released squarely to avoid any damage to surrounding elements. Can be used on single-piston, twin opposing piston and other caliper types and on most car models. Can be operated with 1/2" ratchet or 21mm spanner. Capacity 0 - 65mm.