The Undertaker® Choke Tubes are designed and manufactured for top quality performance. This product has been field tested for optimum diameter producing super full choke patterns (puts 90% of the shot, in a 30" circle at 40 yards) The Undertaker is manufactured in 41L42 chrome-moly, aircraft quality alloy and heat treated. It has a blued finish and is knurled for easy hand installation. Fits all 2-3/4", 3", adn 3-1/2" guns. Designed for lead and copper plated shot in 12 and 20-gauge shotguns.