These receivers are M4A3 mil-contract upper receivers. The finest upper receivers on the market, period. Featuring:

• Machined from 7075 aluminum forgings
• M4 feed ramps
• Marked 'M4' above gas tube inlet hole
• Hard black-anodized finish
• Milled T-marked
• Uppers come with our Mil-Spec completion kit
• Ejection Port Cover comes complete with our no "c" clip tapered pin