ProMag COL27 Standard Black Detachable 10rd 22 LR for Colt M4

This replacement or spare magazine is compatible with your Colt M4. It is constructed of DuPont Zytel polymer with injection molded mag follower and mag spring formed from chrome silicone wire. Made in the USA. NOTE: This mag will not work with Ciener and G.I style 22 conversion rifles.