Aero Precision’s Ejection Port Cover Kit contains everything you need to complete this key part of a stripped upper receiver AR 308 upper receiver. This cover fits the Aero Precision M5 upper receiver, as well as the DPMS LR-308 upper and clones. The LR-308 type upper is used by a large majority of AR 308 manufacturers, so this ejection port cover kit will fit a very broad range of rifles and uppers currently in production. Kit includes: DPMS LR-308 style ejection port cover door Ejection port rod Ejection port cover spring Components are all made of high-grade steel, with a durable matte black finish on the ejection port cover door itself and rod. This is an important assembly needed for completing any 308 upper receiver. Why skimp on such a important part?