Standard O₂ Tank (Subnautica)

The tank is a crafted piece of equipment which boosts the player's oxygen supply by 30 seconds.

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

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