Renfroe HRS Locking Type Horizontal Lifting ClampsAvailable in capacities from 0. 25t to 4t, Renfroe's HRS Horizontal Lifting Clamps feature a spring loaded open and closed position, allowing for single person operation of multiple clamps. Designed to be used only in pairs, these clamps stay in position where they are attached until the spring opening is actuated. NOTE: Must be used in pairs SKU Capacity (tons) Shackle Hole Dia (in.) Max Jaw Open (in.) Min Jaw Open (in.) Cam Thick (in.) Clamp Length