Great features. They fit snugly and help keep your calipers working like new. Their primary purpose is to allow the pads to move back and forth freely so that they engage when the brake is applied and recede when the brakes are released. . A look at your old gear will tell you if you need a new set. Mine were blackened, not smooth. Use anti-seize lubricant when installing fasteners and brake pads. This kit fits both left and right rear wheels, so you only need 1 kit to install both rear brakes.