The Colt AR-15 magazine is a standard factory replacement magazine. This magazine is designed to be compatible with all AR-15 models chambered in the popular 5.56 NATO or .223 Remington cartridge holding 30 rounds of ammunition. The magazine is made from high quality aluminum and features a very nice matte finish. The most important aspect of this magazine is the fact that it is made by Colt so you can rest assured that the magazine will meet and exceed the specifications and tolerances set forth by the factory engineers. You can be all but certain that this magazine will fit perfectly and function flawlessly the same as with the magazine(s) that shipped with your firearm.