The tank is a crucial piece of gear. Without it and you are throwing paintballs back at the other team. The tank provides the pressure to shoot the ball, like the black powder in a musket. Choosing a tank is normally fairly straight forward with only two types of gas- Co2, and compressed air(also known as HPA). Compressed air is normally the best option, as it is more consistent of an output pressure, and easier to refill- and some guns can not even use Co2 where all can use compressed air. Though it can go a bit deeper than that. Some compressed air tanks have a set out put pressure, and some are adjustable, allowing them to be set lower for certain paintball guns that require. Some are also lighter, or smaller for the same capacity.
