Springs / Clips
The spring clip connects the pad to the caliper piston, and is designed to hold the brake pad in position and maintain clearance when not braking. Wire springs perform a similar function, and are often mounted on the back of the pad. In some cases, the brake pads are attached to the caliper housing, which ensures the correct clearance.
Hold down or anti-rattle springs, which can sit directly on the pads, ensure that the pads are properly held in place. This serves to avoid any uncontrolled resonance.