This is a 50-round Taurus GX4 drum magazine, manufactured by Promag.

• 50-round drum magazine
• Fits the Taurus GX4 9mm pistol
• Magazine body constructed of a proprietary DuPont Zytel based polymer
• Blue steel upper magazine tower
• Injection molded magazine follower
• Magazine spring formed from heat treated stainless steel
• Made in USA