An eco tanker is a large airship featured in Jak II. It was a large, truck-like vehicle used to transport eco, either in standard barrels or in large, round containers. They were used by Baron Praxis, specifically the Krimzon Guard, as a means for satisfying the ongoing deal between the Baron and the Metal Head leader. A group of metal heads once managed to steal a tanker and used it to ambush Ashelin Praxis, a few guards, and Jak, who happened to be present in the eastern Bazaar. This event gave rise to the mission "Intercept tanker", which Ashelin described as a way of the Metal Heads testing Haven's defenses. Eco tankers were again featured while docked at the weapons factory: Krew and Baron Praxis evidently planned to use one to transport the piercer bomb with the Precursor Stone inside to the Metal Head nest. Tankers could also be seen docked at the Haven Palace.
The tanker has a large cabin at the front with a mounted turret on top (identical to the one on the back of a HellCat cruiser) and a shovel on the front of the cabin. They typically carry one or two platforms on which the transported items are loaded. Both the cabin as well as the platforms have a crimson red coat of paint.
They are quite sturdy and fast as well, capable of crushing through walls without causing any direct signs of damage (although the vehicle did crash afterwards, it is plausible this was the metal heads' intention). During the fight with Krew on top of the weapons factory you can see multiple tankers stationed next to some platforms, indicating it is one of their storage stations or a similar facility.