The Matthews Vise Grip Plier with Two 5/8 In. Pins provides maximum gripping power on any size pipe up to 6 inches in diameter. The Locking Plier also provides maximum gripping power on both flat and round surfaces with smaller diameters. Caution must be taken when the 5/8 inches pin provided on the adjustment screw is used. Be sure that any off-center weight is toward the locking direction (clockwise); allowing more weight on the other side could loosen the jaws.