The die top and die collar are used for retrieving drilling tools(fishes)from hole. These die taps and die collars manufactured by our factory are made of alloy steel of fine quality. Through tempering and nitriding, they finally run up to high strength and high ductility. The surface hardness of the tapered threads reached above HRC63, so much as to possess the high catching ability, large lifting load and wide fishing range. The die taps and die collars belong to right-handed type and left-handed type. Threads of each type are wicker or triangular. As a rule, the products are provided with wicker threads unless specified in the contract.