The magazine loader was originally designed to load the (100) Round .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. ¬†The process is repeated until the magazine is loaded. ¬†Manufactured from a black, injection-molded, glass-filled polymer.