Hand selected to ensure a proper fit between upper and lower halves. This Wilson Combat AR-15 "better than mil-spec" set accepts all aftermarket and mil-spec internal parts. "Multi" caliber marked. Not "T" Marked for a custom look. Due to the nature of forged lowers, some pitting and machine marks are natural and unavoidable. These marks do not effect function.FeaturesGI style Upper and Lower machined from 7075-T6 Aluminum15" M-Lok handguardClosed Trigger GuardM4-style feedramps for flawless feeding.Will accept all mil-spec parts.Multi caliber Markings (forging stamp may vary)Ash finish