Their unique fixed magazine design creates an ammunition feeding device designed to be contained in or permanently attached to a firearm in such a manner that it cannot be removed without disassembly of the firearm action. Instantly locks into your firearm. The CompMag can be easily removed by breaking your action, removing the lock cover on the magazine, and pushing out the mag with the release tool. The release tool is included with your CompMag. Specifications for CompMag AR-15 5.56/.223/.300 BLK 10 Round Magazine Gen 3: Manufacturer: CompMag Color: Black Fabric/Material: Polymer Magazine Capacity: 10 Round Cartridge: .300 AAC Blackout, .223 Remington Gun Make: AR Platform Gun Model: AR-15 Condition: New Features of CompMag AR-15 5.56/.223/.300 BLK Magazine Gen 3 Allows you to keep the AR-15 features you love on your rifle. (pistol grip, forward grip, retractable stock, and flash hider). No need to "break your action" or deviate from the normal operation of your firearm to reload. Loads easier than a standard magazine. No heavy spring to push each round against. Will fully load on a closed or open bolt. Instant installation. No holes to drill. No need to modify your firearm. Very easy to remove, should you decide to shoot outside of California. Ultra durable and heavy duty, built to last. 150% to 300% thicker side walls than most polymer magazines. CNC turned steel charging handle with glossy black oxide finish. Round counter indicates exactly how many rounds are left in your firearm, including what's in your chamber. Holds the bolt open after the last round is fired. Allows for easy clearing of type 3 malfunctions (such as double feeds). Package Contents: CompMag AR-15 5.56/.223/.300 BLK Magazine Gen 3