The Rock River Arms AR-15 A4 Upper is a high-quality upper receiver manufactured from forged 7075-T6 aluminum with a Type III hard coat anodized finish. Built to mil-spec standards, it features M4 feed ramps, a T-marked Picatinny rail system, standard charging handle port, forward assist compatibility, brass deflector, and dust cover. The flat-top design provides versatile mounting options for optics and accessories. This upper receiver is fully compatible with standard AR-15 components and can be configured with various barrel lengths and handguard systems. The 1/2x28 TPI barrel threading follows standard specifications, while the 7075-T6 aluminum construction ensures durability and reliability. The platform maintains compatibility with AR-15, M16, and M4 components, making it a versatile choice for various build configurations.