The Pro's Pro Automatic Premium Swivel Clamp Base & Bar is equipped with an advanced triggering mechanism which unlocks the clamp base by itself, once the fixed clamp returns to the base. There is a manual release button located on the lever itself as well, in this locked state. Just an eighth of a turn to lock, using a thumb. Suitable with all Pro's Pro machines (except the P100, P103, Comet and V888), as well as other many branded machines. Screws are not included. Compatible with Pro's Pro Universal Clamps.