You're going to need some air. Spray 'em with more paint than they can handle with the Maddog 20 oz. CO2 Paintball Tank! Re-fillable 20 ounce capacity tank BUILT FOR PAINTBALL.This 20 oz. refillable C02 tank meets or exceeds all ASTM, DOT, TC or CGA Standards or Requirements and is compatible with all standard CO2 powered paintball guns. Perfect paintball tank for all levels of play. 5 Year Re-Test Cycle - The date stamped on these tanks is the date the tank was manufactured, NOT an expiration date. Tanks are good for 5 years until they will need to be re-hydrotested.Buy Multipacks to Reload on the Go! All CO2 tanks are shipped empty to comply with Department of Transportation law