The ego can use both low pressure and high pressure tanks. The only difference between the two when using an ego is the possibility of shoot down with a low quality low pressure tank. So a high pressure tank would be your best bet and is the most common air system used on an ego, but if you need to use a low pressure tank for various reasons make sure it is a name brand as they generally have the best recharge and prevent shoot down (ie crossfire, mac dev, etc). As for adjustable tanks you will want to set your tank at around 550-600psi if you are using it in conjunction with the stock regulator, if you are using a gas thru grip then 300-320psi will be the optimal pressure for the ego and adjust for velocity.
