If you need a portable solution for CO2 these paint ball tanks are the answer. When you need a bit more gas than you can get from a 16g cartridge these refillable tanks are the perfect solution.
Available in 12, 20, 24 oz sizes (9 and 16 coming soon) Whether its a custom kegerator, a jockey box, or even a serving backpack! You should be able to find the perfect size for your project.
These are sold empty and need to be filled at your local refill station.
If you live in Calgary the perfect place is MR Paintball, you can get them filled on the spot, and tell Richard I said hi :-)
If you live in Regina go see Kevin at Prairie Brew Supply, he will also fill them on the spot.