Carlsons choke tube long beard xr 12ga ported.665 invector ds FEATURES-Browning Invector DS-12 gauge-Turkey choke-Diameter: .665-Matte black finish-Shot-Lok technology**Not for use with steel shot** Other Features: Manufactured from 17-4 stainless steel,specially designed to produce the best patterns when shooting winchester longbeard xr loads 25% longer parallel section thus throwing tighter & denser patterns.Reduced pellet deformation & shortend shot string means less flyers