The Lee taper crimp die is hardened steel designed to overcome crimp problems caused by poor die design. These dies offer little or no advantage when used with 1986 or newer Lee dies as the crimp angle is already a modified taper crimp. Jacketed bullets must have a crimp groove (Cannelure). shellholder sold separately. Comes shipped with a plastic storage case. Specifications: - cartridge: 40 S&W/10mm auto - number of dies: 1 - die type: taper crimp - threads: 7/8 inch -14 - shellholder included: no - storage box included: yes