San Tan Tactical Upper, 223 Rem, 556NATO, Black, FT STT-15-LT-PILLAR-UPPER San Tan Tactical PILLAR(R) Truss Pockets For Increased Structural Rigidity. - Cut From A Single Billet Of 7075 -T651 Aerospace Grade Aluminum. - Shell Deflector - Machined In T Markings For Easy Optic Relocation. - Machined With M4 Feed Ramps. - Machined To Mil-Spec Standards. - Interfaces With All AR15/M16/M4 Weapons Systems And Accessories. - Accepts ALL Known Handguards Without Modifications. - Mil Spec Type III Class II Hard Coat Anodized Black - Compatible With All Known Battery Assist Levers On The Market Today. - Backed By STT's Unmatched Lifetime Warranty. - Made In The USA. - Does Not Include Port Door Assembly.