game prop design: Sci Fi Oxygen tank

Game prop Concept design and final rendering of Oxygen tanks for incoming sci-fi browser game (2d),
design info:
Game will be set in the future, +150 years from now, it will be placed on planet that resembles our Mars... Humans will be divided in factions, and they will be living in small settlements, in these oxygen tanks they will store most valuable and basic aspect for living - oxygen.