Wiseup 2x U Shape Silicone Rubber Locking Plug for GoPro HD Hero 3+ 3 2 1 Camera Compatible with GoPro HD Hero 3+ 3 2 1 The U shape of this locking plug inserts between the legs of the click-in tangs portion of the camera mounted quick disconnect mount, after the camera mounted clip legs are inserted into the female receiving sticky back tape mount It's more for high speed applications like auto racing, as it keeps vibration down so the camera doesn't rattle and this plug helps ensure the legs can't bend in and accidentally release the camera