The ProMag AR-15 Magazine offers reliable performance with 20-round capacity for .223 and 5.56x45MM rifles and carbines featuring durable steel and polymer hybrid construction with a black oxide finish.ProMag AR-15 / M16 Compatible Magazine20-round capacity for .223 and 5.56x45MM ammunitionSteel upper with polymer lower housing constructionProprietary DuPont Zytel based polymer bodyHeat-treated chrome silicon wire magazine springInjection molded magazine followerBlack oxide finishMade in the USA with lifetime guaranteeEngineered for AR-15 and M16 platform rifles and carbines this magazine combines the durability of steel with lightweight polymer construction for reliable feeding and long-lasting performance in tactical and sporting applications.