Pro Mag drum magazine is compatible with your AR-15 with Glock style mags. It is constructed of DuPont Zytel polymer with injection molded mag follower and mag spring formed from chrome silicone wire. Made in the USA.
Specifications:

Caliber	9mm Luger
Capacity	30rd
Finish	Black
Model	Standard
Material	DuPont Zytel Polymer
Type
Model Fit	AR-15 with Glock Style Mag
Brand Fit
Capacity	30