POF-USA upper receivers include a Modular Railed Receiver™, a free-floating monolithic top rail system made of billet machined 7075-T6 aircraft aluminium alloy, an oversized heat-sink barrel hunt, and a black anodized charging handle. This two piece A3 flattop upper receiver is available with a NP3™, black anodized, or olive drab Cerakote™ finish.