The Magpul AMAG 21 SG9 features a stainless-steel body with polymer sub-components. Magpul SIG magazines come with many of standard proven features, including a high-visibility, controlled-tilt follower, stainless-steel spring, flared floorplate that's easily removable for cleaning and routine maintenance, paint-pen dot matrix for magazine marking, and capacity-indicator windows which begin at five (5) rounds, and continue along the spine of the magazine in one(1)-round increments. Like all the Magpul polymer products, the AMAG 21 SG9 is designed, engineered, and manufactured only by Magpul for absolute reliability every time you use them. FeaturesCorrosion-resistant, stainless-steel magazine bodyHigh-visibility, controlled-tilt followerStainless-steel spring for longevity and durabilityFlared, easily removable floorplate for easy maintenanceCapacity indicators starting at 5 rounds, continue in 1-round intervalsPaint-pen dot matrixCompatible with all P320 / M17 frame size