The Jorgensen Cabinet Master Bar Clamps are ideal for flat panel, box, cabinet, frame and panel doors assemblies or any other project that requires squareness or evenly applied pressure. Large plastic jaws assure the distribution of clamping pressure over large areas. The jaws stay parallel to assure squareness and prevent work pieces from bowing or lifting. Built in clamp stand allows clamps to stand upright for one handed use and easier/quicker sliding head adjustment. The sliding head can be reversed on the bar and the clamp then acts as a spreader. Opening capacity is 48 inches, clamping faces are 3-3/4 in. height and 1-7/8 in. width, high-carbon steel bar is 1-3/16 in. by 3/8 in., screw is 5/8 in. cold-drawn steel with special, smoothly cut acme threads, large easy to grip handle, and load limit is 1,500 lbs.