These chokes start out as 17-4PH stainless steel bar material that is then bored and turned with exacting precision by the latest CNC equipment. Internal geometry features a tapered area that finishes in a parallel section to create the most uniform and consistent patterns possible. Because the choke extends beyond the muzzle, use of a more gradual internal taper is possible. Finish is matte black, and each is laser-engraved for identification without having to remove the choke. Ext. range tubes are ported and feature straight rifling for superior pattering. 12-gauge only.