This is the standard 20 oz. paintball CO2 bottle, made by Tippmann.  The 20 oz. bottle will fire about 900 paintballs per fill.  Like all paintball CO2 bottles, this bottle requires retesting after 5 years from the manufacture date.  The standard 'ASA' valve will connect to any of the Tippmann paintball guns.  A 3,000 PSI burst disk is on the side of the Valve.

This tank will ship EMPTY.  You must have it filled at a sporting goods store, a paintball store, or a personal fill station before use.

CO2 tanks to do not need a gauge to tell how full they are.  The liquid CO2 is measured by weight, not pressure.  If you have a scale you can measure your 'empty weight' and compare that to the current weight of your tank to see how much CO2 is in it.