The Enhanced Ejection Port Cover is a drop-in upgrade designed to provide an improved installation process, physical strength, and corrosion resistance over the standard USGI ejection port cover. Traditional stamped-steel ejection ports are malleable, prone to corrosion, and require tools to install. The Enhanced Ejection Port Cover snaps into place easily without having to remove your hand guard or barrel nut, wind any loose springs, or adjust small e-clips. Constructed of impact-resistant injection molded polymer, it is corrosion resistant and will not bend or deform from impacts. Compatible with USGI-pattern AR15 upper receivers that accept USGI ejection port covers. Specifications for Magpul Industries Enhanced Ejection Port Cover: Manufacturer: Magpul Industries Gun Model: M16, M4, AR-15 Fabric/Material: Polymer Condition: New Features of Magpul Industries Enhanced Ejection Port Cover Installs easily in seconds Direct replacement for USGI ejection port cover Durable,?injection-molded polymer construction Corrosion resistant components Will not bend or deform from impacts Package Contents: Magpul Industries Enhanced Ejection Port Cover What firearm models does the manufacturer say Magpul Industries Enhanced Ejection Port Cover is compatible with? The manufacturer says that Magpul Industries Enhanced Ejection Port Cover is compatible with AR-15, M4, M16