A brake caliper device is necessary if you are changing the brake pads on an automobile and really helps to prevent harm to the pistons while dealing with the brake pads. A brake caliper device retracts the pistons back to the real caliper therefore the brake pads can simply be eliminated and changed. The device itself fits on the piston at one end. In the additional end, you will see a handle enabling rotation. With each rotation, the piston will blowing wind in to the caliper itself.