Using For Lifting Steel Vertical.Only A Single Hoisting Operation Or Using Of Two Complementary, Only A Single Vertical Clamp Lifting Weights Is The Largest Rated Load.Lifting Must Be Locking Up The Handle So That The Spring Tension;Unloading When The Locking Handle Down, Relax Spring, And Clamp Plate Can Bu Separated.The Vertical Lifting Clamp , The Proof Load Is 2 Times Working Load Limit,The Breaking Load Is 4 Times Working Load Limit.