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.