The Scenario Arms "6 pack" tank caddy was designed to allow the easy transportation of up to six 20oz co2 canisters to and from games. The padded dividers can also be folded inward to allow you to transport 2 or 4 tanks as well as misc. other gear like rags, hand chrono's, barrel swabs, allen wrenches, or even extra water bottles
The tank caddy is constructed from the same durable nylon material used to make most duffle bags, and is available in either woodland, or black. The bottom of the caddy is reinforced to retain it's flat shape when carrying your gear, and it will not bulge downard while being carried with your full co2 tanks in it. The padded dividers keep your tanks from noisily banging against one another, and can also be repositioned to allow you to carry other gear than just your tanks. When not in use, the caddy can also be folded flat to allow for easy storage.
The Scenario Arms Co2 Tank Caddy is newer, so it should be commonly available, both new and used.