TacFire Mil-Spec Buffer Tube Black Hardcoat Anodized Aluminum For AR-15 Tacfire's AR15 Mil-Spec Buffer Tube Is Made From 6061-T6 Aircraft Grade Aluminum, Matte Black Anodizing With Type III Class II Hard Coat For Best Wear Resistance. It Has The tightest Tolerance Control For Zero-Gap fitment With Polymer Stock And Receiver To Meet Most Demanding Silent operations. Compatible With Mil-Spec Butt Stock. Material: Aluminum Finish: Black Hardcoat Anodized