The Amend2 30 round magazine is a sturdy, reliable 5.56x45 NATO (.223 Remington) AR15/M4/M16 magazine made of an advanced polymer material. It is a light, durable and excellent alternative to the standard M4/M16 USGI aluminum magazine. Product Features Sturdy, impact-resistant polymer with textured grip 4-way anti-tilt, self-lubricating follower Heavy duty, non-memory, and non-corrosive stainless steel spring Made in the U.S.A.