Forward Controls Design Single Dimple Ejection Port Cover Olive Drab Green EPC ODG single dimple. EPC (Ejection Port Cover) is based on TDP dimensions with thoughtful Forward Control touches. Billet machined from 7075 aluminum and hard coat Type III anodized it incorporates features we think many will find useful. EPC has two "tabs" flanking the cutout for the port cover spring. These tabs allow the EPC to rest on the upper at a greater angle when it's in the down/open position which provides more space between the port cover and lower receiver. Their job is to better allow the user's finger to get underneath the port cover when he wishes to swing it up/close. Left: TDP ejection port cover. Right: EPC. Both in the down/open position. Please note that depending on the upper receiver the area below the ejection port cover will vary in thickness which affects the angle of the EPC when the port cover is open/down. Another feature is a shallow circular depression on the side of the EPC to provide texture tactile feedback to the user's finger when he's closing the EPC. A flat surface provides nothing to the user to differentiate one surface from another it also provides no traction. A shallow circular depression on the left side of the EPC does both. Forward Controls Design incorporate flat surfaces with care as they have their uses. In this case EPC's exterior surface is treated as a control surface where a flat surface rarely makes sense. EPC is compatible with TDP spec upper receivers. Specifications for Forward Controls Design Single Dimple Ejection Port Cover: Manufacturer: Forward Controls Design Finish: Type III Anodized Fabric/Material: 7075 Aluminum Weight: 0.3 oz Package Contents: Forward Controls Design Single Dimple Ejection Port Cover Port cover hinge pin Spring Forward Controls Design EPC ODG single dimple: Single Dimple Ejection Port Cover Olive Drab Green