Check the listing for details. Madbull Airsoft Black Python Ver.2 6.03mm Tight Bore Barrel (590mm) for PSG1. Condition: New. Listed at 45.00 USD. HAND SELECTED Version 2 Black Python 590mm Tight Bore Barrel. Apply to PSG1 series Black Python is our experimental product. By using a hard coating process, our barrels can provide the smoothest inner barrel surface and a reinforced structure.We QC each barrel by a very special process, please check our article on ArniesEvery single barrel has been carefully hand chosen and well-packaged. What is difference between Ver 1 and Ver 2?Based on the feedback from users, we did a lot of improvements on the new Ver 2's Ver 2 is being made with a new machine and new coating process. Features: - CNC machined aluminum - Tight air seal construction - Smooth and slick surface -Precision 6.03mm diameter - See more at:http://www.airsoftmegastore.com/8828-madbull-black-python-455mm-tightbore-barrel-6-03mm-jag-mb-barl-455mm.aspx#sthash.a0rOdFrg.dpuf- CNC machined aluminum - Tight air seal construction - Smooth and slick surface -Precision 6.03mm diameter - See more at:http://www.airsoftmegastore.com/8828-madbull-black-python-455mm-tightbore-barrel-6-03mm-jag-mb-barl-455mm.aspx#sthash.a0rOdFrg.dpuf- CNC machined aluminum- Tight air seal construction- Smooth and slick surface- Precision 6.03mm diameterSpecifications: Material: Aluminum Diameter: 6.03 mmNote: Ready to use right out of the box, though professional installation is recommended/may be required. Please use only ultra high-quality precision seamless BBs in your gun after installing this barrel, as inferior grade BBs (i.e. BBs from sporting goods stores) WILL jam inside this barrel.