This is the ProMag FN Five-seveN 5.7x28mm 55 Round Drum Magazine.

Save time and your thumbs with the help of this high-quality 55-round drum magazine from ProMag!

Featuring a steel upper magazine tower and a proprietary DuPont Zytel based polymer drum, this magazine delivers superior durability while remaining lightweight and corrosion resistant.

You’ll find an injection-molded polymer follower keeping all 55 rounds perfectly aligned and side-facing witness windows to help keep track of them. From breaking in your new Five-seveN at the range to mag dumping in the backyard with friends, this is the drum magazine for you! 

Order a drum or two and forget about reloading at the range!