You can find the Aero Precision M4E1 Threaded Assembled Upper Receiver OD Green here.

The Aero Precision M4E1 Threaded Assembled Upper Receiver features a new angular machined design for a unique look and the same enhanced body profile as the Aero Precision M4E1 Enhanced Upper Receiver, but threaded to accept a standard AR15 barrel nut. Forged from 7075-T6 Aluminum, precision machined to work with all Mil-Spec AR15 parts, and includes the port door and forward assist pre-installed. Designed to pair perfectly with the M4E1 Lower Receiver, giving you a billet-looking receiver set at a fraction of the billet price.

Weight: 8.65oz
Color: Anodized OD Green