Designed to fit your ar-15 pattern firearms chambered in 5.56x45mm or 223 remington.The clear polymer body allows you to actively monitor your ammunition.A high carbon steel spring assists the linked follower to facilitate quick and easy loading.Not compatible with some ar-15 / m16 / m4 receivers that do not have the same internal and external dimension of a mil-spec lower receiver.Caliber: 5.56x45mm NATOCapacity: 50rdModel: AR-15Material: PolymerCapacity: 50