Promag magazine loader was originally designed to load the 100 rd.223/5.56 beta magazine.The loader is slipped over any ar-15/m16.223/5.56 type magazine.Five cartridges are dropped in and loaded by depressing the plunger, repeating the process is until the magazine is loaded,Caliber: 223 RemCapacity: 5rdFinish: BlackModel: USGIMaterial: PolymerModel Fit: AR-15, M16Brand Fit: AR-15 PlatformCapacity: 5