Single rope clamshell grab with contractile guide bar is an efficient tool for loading and unloading sands, coal, mineral powder and bulk chemical fertilizer, which is suitable to the crane with single drum used on port, yard and use altitude restricted working site. The characteristic of grab is simple structure, novel opening and closing/expanding and contracting mechanism, convenient operation, reliable action. The lifting capacity of crane is normally 5t-25t. The grabs are widely used in ports, electricity, vessel, metallurgy, preservation and transportation.