The MAGPUL AMAG 21 SG9 SIG P320/M17 9mm 21-Round Stainless Steel Magazine is designed specifically for shooters who need a durable metal magazine for their SIG P320 or M17 9mm handguns. The AMAG 21 SG9 features a tough stainless-steel body combined with polymer sub-components to deliver reliable feeding and long-lasting performance. This magazine includes a high-visibility, controlled-tilt follower, a corrosion-resistant stainless-steel spring, and a flared floorplate that makes disassembly for cleaning simple. The MAGPUL AMAG 21 SG9 also has capacity indicator windows starting at five rounds and continuing in single-round increments, plus a paint-pen dot matrix for easy marking. Made in the USA, the MAGPUL AMAG 21 SG9 provides trusted Magpul quality for pistols that require metal magazines.