The aquapack was a short-lived accessory meant to operate underwater in the same way a steampack operates in the air. Those who have this item can find it in the Accessories section of inventory. When equipped, it looks like a large bubble-shaped pack on the player's upper back. The upgraded versions of the aquapack are Diamond Aquapack and Onyx Aquapack.
How to Obtain
It is currently (January 2016) impossible to obtain this item except by finding someone who happens to have one and is willing to trade it to you in a market world.
How to Use
While it is possible to equip the aquapack, at present (January 2016), it merely works as a steampack. If you own this item and want to equip it, simply drag it to your Accessory bar in place of your normal steampack.
First released as part of a beta build. Unscrupulous beta testers found an exploit that let them transfer the item to their non-beta accounts, and they began selling them to non-beta players as rare items for exorbitant prices. Soon after this, aquapacks were released to the general public as a craftable item. Within a very short time, however, the ability to craft them was removed, although the item itself was permitted to remain in player inventories. Today (January 2016), a handful of aquapacks still exist in game as essentially useless accessories.