Increases reliability in all 1911 pistols; Aircraft grade certified stainless steel tube resists corrosion; .025" tube walls - thickest in the industry; Tubes are heat treated for maximum durability and service life; Patented extended skirt, anti-tilt all metal follower ensures lock back and increases feed reliability in all .40 S&W 1911 pistols; Maximum tensile strength heavy-duty spring for long service life, enhanced feeding and positive slide stop operation; Removable .350" plastic base pad for easy maintenance and versatility with different base pad options; No other magazine on the market can compare for proven inherent reliability, durability and the ability to remain loaded for long periods of time without damage; Metal spacer ensures proper feeding with factory .40 S&W ammo