Airsoft Masterpiece .40 S&W; STEEL Threaded Fix Outer Barrel for Hi-CAPA 5.1**Please note: installing parts / assemble /fitting airsoft gun will need intermediate knowledge; for expert or airsoft gunsmith. Please refer to your airsoft gunsmith for proper installation / fitting. Fitting may be needed as the condition of each airsoft gun might be different.Product Brand:Airsoft MasterpieceProduct Code:OB40SW-T-TM51Material:Stainless Steel