Product Description The ProMag SIG-A21 magazine is designed for Sig Sauer P365-series 9mm pistols and offers a 20-round capacity for extended range time and fewer reloads. Built with a heat-treated steel magazine body and a black oxide (blue steel) finish, it is engineered for durability and consistent performance. Inside, an injection-molded follower and a precision-wound spring made from heat-treated chrome silicon wire help promote reliable feeding. Made in the USA and backed by ProMags lifetime guarantee against manufacturers defects. Product Highlights 20-round capacity 9mm magazine compatible with Sig Sauer P365 / P365X / P365XL pistols Heat-treated steel magazine body with black oxide (blue steel) finish for corrosion resistance Injection-molded magazine follower for smooth, consistent operation Heat-treated chrome silicon wire spring for long-lasting tension and reliability Made in the USA and backed by a ProMag lifetime guarantee against manufacturer defects Specs Brand Name: ProMag Industries Manufacturer Part Number: SIG-A21 UPC: 708279015908 Firearm Fit: Sig Sauer P365 / P365X / P365XL Caliber: 9mm Capacity: 20 rounds Body Material: Heat-treated steel Finish: Black oxide (blue steel) Follower: Injection molded Spring Material: Heat-treated chrome silicon wire Country of Manufacture: USA Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the products manufacturer.