This 55-round drum magazine is designed for FN 5.7x28mm AR-style carbines, offering high-capacity performance and reliable feeding. Built with durable materials and reinforced components, it delivers consistent operation and long-lasting durability for extended shooting sessions. Note: This magazine is not compatible with the FN Five-seveN USG pistol. Product Details Capacity: 55 rounds Compatibility: FN 5.7x28mm AR-style carbines Not compatible with FN Five-seven USG 5.7x28mm pistol Material: DuPont Zytel based polymer magazine body Blue steel upper magazine tower Injection molded follower Heat-treated stainless steel spring Made in the USA