Ultra High Capacity Tank (Subnautica)

The High Capacity Tank is an piece of upgrade to the regular tank. It is crafted by using the Workbench, which boosts the player's oxygen supply by 60 seconds. This is twice the norm.

The player can carry multiple tanks at a time to further increase their oxygen capacity (but lowering space for other things). The High Capacity Tank also take up four slots in the player's inventory.

While each High Capacity Tank adds to oxygen, it also adds to your current weight, therefore decreasing the player's swimming speed.