CLOSE-RANGE MID-RANGE & LONG RANGE CHOKE TUBES WITH CASE - Our Waterfowl Extended Choke Tubes are manufactured from a tough high grade stainless steel to withstand steel shot Hevi Shot and other heavy tungsten shot. Due to the thin wall design of the Optima HP choke system we had to use a tougher material in the Mid Range & Extended Range tubes so that you don't have to worry about the choke tube swelling and sticking in the shotgun's barrel. These choke tubes feature a 25% longer parallel section in the choke thus throwing more consistent patterns. Each choke tube is knurled on the end to allow for quick and easy removal. Each choke tube has the constriction and size laser marked on the end and body for easy reference. - Steel shot may be used through these choke tubes with exceptional results. Do not shoot steel shot larger than BB or any steel load faster than 1550 FPS through the Full or Extra Full Constrictions.