Beretta’s Optima-Choke HP Black Edition extended choke tubes are manufactured from high-strength steel for significant corrosion resistance and the ability to withstand the rigors of steel shot. They extend from the muzzle by 0.78 in (20mm) and screw in and out without special tools. Optima-Choke HP tubes are fully interchangeable on all Beretta barrels threaded for Optima-Choke HP. Optima HP tubes are not interchangeable with standard (non-HP) Optima tubes; using an HP tube in a non-HP Optima barrel can damage the tube and barrel.