97mm UNICORN Nitroflon Coating 6.03MM Ultimate Precision Inner Barrel For GBB In common use TokyoMarui G17 , HI-CAPA4.3 VFC-G17 WE-G17 1. Material: Brass with Nitroflon Coating 2. 6.03mm Ultimate Precision Inner Barrel 3. AEG specifycation, included AEG 60 degree bucking, 50 degree Hop-Up Nub and brass ring