-> GRIPHOLD Heavy Duty Pipe Wrenches have been designed to is-4003 (part ii) - 1986. -> Heavy Duty Handles are made of SG iron and aluminium alloy for maximum strength. -> Movable and fix jaws are made up of high strength alloy steel for longer life. -> Handle has been designed to ensure easy and untiring grip. -> Knurled adjustable nut has been used to ensure easy setting. -> Spring set has been designed for gripholding movable jaws. -> Metallurgy of SG iron handle is as per is-1865-1991. -> Torque test/load test is done as per is-4003 (part ii)-1986. -> Percentage elongation test for the handles is done as per is-1865-1991.