DURAMAG Speed magazines are a truly improved USGI magazine. DURAMAG Speed bodies are constructed of 6061-T6 aluminum and are type-III anodized to the mil-spec. This battle-proven magazine is lightweight, durable and feeds every time. DURAMAG SPEED mags have been the magazine of choice for OEM, Law Enforcement and Military Units throughout the world and are safe for extended storage while loaded. DURAMAG will not flex or swell like polymer.