Four rope clamshell grab is an efficient tool for loading and unloading sands, coal, mineral powder and bulk chemical fertilizer, which is suitable to the crane with two hoist drums used on port, yard and use altitude restricted working site. The characteristic of grab is simple structure, convenient operation, reliable action. The lifting capacity of crane is normally 3t-100t. The grabs are widely used in ports, electricity, vessel, metallurgy, preservation and transportation.