For ar-15 pattern firearms chambered in 5.56x45mm or 223 remington.The drum feeds alternately from the left and right sides using two independent follower belts to maintain a balanced center of gravity while firing.Features steel-reinforced feed lips for added durability and reliable feeding.This package includes the kci usa 100 round drum, operators manual, carrying pouch, graphite lubricant, and loader.Caliber: 5.56x45mm NATOCapacity: 100rdModel: AR-15Material: PolymerCapacity: 100