Cross Machine Tool Co., utilizing the latest machining technologies, offers high quality products that you'll be excited to own.The Ultra Precision Upper Receiver is a high quality billet AR-15 receiver, machined from 7075-T6 aluminum. This AR upper receiver features increased wall thickness for greater durability.Features: Billet 7075-T6 aluminum MIL-SPEC Engraved T-marks M4 feed ramp cuts Type III hardcoat anodized Flattop Picatinny rail Accepts standard port door cover and forward assist Weight: 8.2 oz Lifetime warranty