This is an AR-15 Cammenga EasyMag 30rd. Magazine. Cammenga is leading the development of next-generation firearm magazines with the CAMMENGA EASYMAG series. The Model EM3-556, 30 round M16/AR-15 magazine features an open case design that allows for fast loading, unloading, and cleaning. The casing, follower, and baseplate are made of high-strength 1050 spring steel and are finished with a two-layer anti-friction coating. A large tip-proof steel follower and chrome silicon main spring provide optimal feeding performance and long lasting reliability. The CAMMENGA EASYMAG eliminates the need for a separate loading device. The EASYMAG can be loaded twice as fast as conventional magazines when using loose ammo, and can also be loaded like a conventional magazine using stripper clips, and can be opened and cleaned in seconds. Click the link below to go to their webpage and check out the video of this magazine, it is impressive.