ProMag COL27 Standard 10rd 22 LR Fits Colt M4 Black DuPont Zytel Polymer

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.