This replacement or spare magazine is compatible with your AR-15 SMG, Colt Carbine. 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	50
Finish	Black
Model	AR-15
Material	Polymer
Type	Drum
Model Fit	AR-15
Brand Fit	AR-15 Platform
Max Capacity	50