Version 1 - NON-Adjustable. Discontinued by the manufacturer and is no longer available. Sorry! September 2009. Order this and you will receive Version 2 CO2 Cap only. Cartridges vary in length and may not puncture on the first pull. If this happens, check the CO2 cap adjustment. Turn the adjustment screw in 1/2 turn and try the trigger puncture again. Repeat until you get a puncture and a good seal. From Tippmann: New TPX Pistol CO2 Upgrade Kit and Tech Support Over the past few months, feedback regarding our new TPX Pistol has been overwhelmingly positive. The new product has generated a tremendous amount of interest and excitement among paintball players around the globe. However, an issue regarding the pistol has surfaced. It appears the dimensions for CO2 cartridges vary far beyond our initial tests, and have resulted in some cartridges not puncturing. Although we tested numerous brands, we have discovered that certain types of cartridges may not puncture on the first pull. If you’ve noticed this issue, please contact us at 1-800-533-4831 or visit www.tippmann.com, click on the CO2 Upgrade Kit link and simply complete the appropriate TPX form with your serial number. We’ll send you a free CO2 Upgrade Kit including a new cap with an adjustable set screw that adjusts for various CO2 cartridge sizes, as well as a new, easy-to-install pin assembly. If you have experienced any other issues, whether it is velocity, efficiency, or paint breakage related, we encourage you to visit our new TPX Tech Support program on the Tippmann web site to learn more about troubleshooting, installation and maintenance of your TPX Pistol. There are also some helpful tips on how to correctly pick paint and properly load a magazine. And if you can't find what you’re looking for in the videos, you may always contact our Tech Service Team at 1-800-533-4831, or 1-260-749-6022. We apologize in advance for any inconvenience this may cause. We actually became aware of these issues via customer phone calls and paintball forums. We are pleased to offer this free upgrade kit which will make the TPX pistol more adaptable to the many different CO2 cartridges in the marketplace. Thank you for your continued support and ongoing communication – it’s appreciated.