UP Aqua - CO2 Aluminum Cylinder (Paint Ball valve - A-137/138/159/140) - (0.6/1/2/2.8L)Complete Co2 System (Nano Set) w A 137 A 138 *** Cylinder comes with Full Tank Co2 *** ***Check out our complete guide to the Co2 System set up. ***Advantages of purchasing through us*** The advantage of buying the Co2 System from us is that you can simply bring your empty Co2 cylinder (with the regulator attached) to our store. We can do an instant refill for you by exchanging your empty cylinder with a full cylinder with your regulator re assembled.