Standard design clamp for vertical lifting of steel plates and steel structures. The spring-loaded tightening lock mechanism assures a positive initial clamping force. Clamps are equipped with a safety mechanism, ensuring the clamp does not slip when lifting force is applied and when load is being lowered. High-frequency quenching of die-forged special alloy steels gives greater durability to the cam. Hardened tool steel serrated gripper and forged head & gear. Securely grips sheet until release ring is pulled. Safety factor is 2 to 1 & meets ASME B30.20 standards. PERFECT FOR HEAVY PLATES: Able to vertically lift heavy duty plate and sheet material that weigh up to 2200 lbs! Not designed to be used on stainless steel or aluminum plates. STRONG JAWS: The hardened, durable steel serrated jaws open 0-0.866”.