Made from glass reinforced polymer, this patent pending magazine features a unique follower system that allows for double capacity from a normal AR magazine without being bulky or cumbersome. Designed to shoot both .223 Remington & 5.56X45mm ammunition, the Schmeisser S60 will give you an instant capacity upgrade over the standard AR mag at an affordable price for your AR Carbine or Pistol. This model of the S60 comes with a viewing window to give the user a visual confirmation of the remaining ammunition available.