Tanks

A tank is an object that can contain any type of gas. Tanks come in different sizes (volumes) and colors. Most of them can be carried in your hand, some even on your belt.

Volume vs Pressure
Tanks have different volumes and pressure. Volume is the size of a tank and pressure the amount of gas per size unit. Thus the amount of gas inside a container is its volume multiplied by its gas pressure.

Canisters are very large tanks that usually come with highly pressurized gas and as such can be used to quickly refill a high number of smaller tanks. To do so, simply left click on a canister with a tank in your hand to attach it. Click again to open the refill menu.

Types
Emergency oxygen tanks have a molar volume of 3 units.

Extended-capacity emergency oxygen tanks have a volume of 6 units.

Gas tanks have a volume of 10 units.

Canisters have a volume of (???) units.

Both emergency tanks can be carried on the belt, both gas tanks in a hand and canisters can only be pulled or pushed.