This is the Beretta 21 .25 ACP 9-round magazine, made by Mec-Gar.

World-renowned Mec-Gar does it again – manufacturing  Mec-Gar’s blued steel body ensures durability and a sleek look. The stainless steel follower with an anti-tilt design guarantees smooth feeding and reliability. Its sturdy steel baseplate enhances longevity, while the side-facing witness holes allow for quick round counts. This magazine not only improves your shooting experience but also brings peace of mind with its consistent performance. Enhance your Beretta 21 today and experience the difference!