Atotal choke system for the waterfowler. Made of black oxided 174 stainless. Ports add wad stripping capabilities for superior patterns with lead, steel, tungsten and bismuth. The decoy (D) is designed for shots out to 30 yards when hunting over ddecoys. Passing tube (P) is designed for average shots of 30 to 45 yards and extended range tube (X) for those rare shots in excess of 45 yards. This tube will shorten your shot string‚ Throw up a wall of pellets for the impact qualities of lead!