Patternmaster Black Cloud Choke is a full constriction choke (.690) that is compatible with the Black Cloud Ammunition or any ammunition with a "Flight Controlled" wad. They have also been proven effective with other brands of shotgun ammunition. This choke interchanges with Benelli M2, Super Black Eagle II, and Beretta Optima Plus just to name a few. ***Disclaimer: Ammunition with a "Flight Control" wad may not pattern as well if shot through a ported barrel.