The Gun Boss pull-through system cleans and protects firearms by pulling fouling out of the muzzle"" rather than back into the chamber and action. It comes in a compact"" weather-resistant"" molded case. Non-marring aluminum connectors and adapters"" phosphor bronze brushes"" and coated steel cables protect your bores. Every tool snaps securely into place on the high-quality"" oil-resistant tray. Fits .17 - .45 cal."" 20 ga. & 12 ga.