You can find the Nordic Components Stripped Extruded AR-15 Slick Side Upper Receiver here.
The Nordic Components Stripped Extruded AR-15 Slick Side Upper Receiver is manufactured from extruded 7075-T6 Aluminum and Type III Hard-coat Anodized. The slick side upper receiver eliminates the dust cover and forward assist for cleaner lines and a weight of only 10oz.