Canisters are the containers which most resources are contained in when they arrive to your ship.
The resources can be accessed using loaders connected to pipes, or in some cases the canister will be attached directly to the relevant equipment, such as with the FTL Drive.
When the canister is empty, it will disappear and automatically be replaced if there is an available canister of the same type.
There is currently no way to create or fill a canister.
Fluid resources can only be sold to a trader while in a canister.