The clamp locks closed and opens when the locking tab is released. Clamps can be attached at any point on tubing without disconnecting tubing. When they are not in use, clamp can be clipped to tubing without restricting flow. Jaws are 27mm (1-1/16") long and total length is 59mm (2-5/16") long. Jagged jaws will close tubing with a wall of .82mm (1/32") or thinner. Clamps are made of acetal and they can be autoclaved. Come 12 clamps per package.