The brake caliper is the assembly which houses the brake pads and pistons.

A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a “rotor” to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into waste heat which must be dispersed.

Hydraulically actuated disc brakes are the most commonly used form of brake for motor vehicles, but the principles of a disc brake are applicable to almost any rotating shaft. The components includes the disc, master cylinder, caliper (which contains cylinder and two brake pads) on both side of the disc.