Beretta Optima-Choke® HP tubes stand up to the heat of competition. Manufactured from high strength steel and finished in a nickel-alloy coating, these chokes guarantee significant corrosion resistance and have the ability to withstand the rigors of steel shot. Optima-Choke® HP tubes are fully interchangeable on all Beretta barrels that are threaded for Optima-Choke® HP. No steel shot tighter than MOD.
Big Book Catalog, Issue:68, Page:588
Only use Optima HP choke tubes in these OptimaHP shotguns: SV10 Perennia, SV10 Prevail, A400 Xplor and UGB25 Sporting.