The Noveske Engraved AR-15 Ejection Port Cover fits standard mil-spec upper receivers. Each port door now includes the port door rod, spring and clip (clip is not used for 4th Generation Noveske uppers). FeaturesMil-spec port door (dust cover) for AR-15Laser engraved with Noveske logos or calibers5.56, 300 BLK, 338 ARC and 6mm ARC are marked on both inside and outsideFlaming Pig, Noveske Cross, and Ghetto Blaster are marked on the inside and are blank on the outside