The MC16 fits AR15/M16 .223/.556 x 45 aluminum magazines, doubling their available ammunition capacity and allowing for faster reloading. Wide gap between magazines allows for quicker magazine changes. Made of lightweight, light-density polymer. Improved durable design won't scratch or deform magazines. Easy-to-use screw-tightened design. No gunsmithing required. Lifetime warranty. Made in Israel. Weighs only 0.13 lbs. Dimensions: 3"H x 2.3"W.