The classic most reliable design still the best available. A heat treated stainless steel body with steel follower and heavy duty spring provides flawless feeding. Outstanding reliability with all types of ammo including todays popular hollow point bullets. Each magazines includes one thick and one thin base pad and screws for each allowing you to choose which pad you would like to install. Leave the pad off for a flush fit install the slim pad for a low-profile or install the thick pad for use with a magwell.