Apollo service module fuel cell. Three cells were used to generate power for the spacecraft and water for the astronauts.
Fullsize image: https://diqn32j8nouaz.cloudfront.net...l_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net..._fuel_cell.jpg
Previously:
https://www.homemadetools.net/forum/...861#post156375
https://www.homemadetools.net/forum/...044#post171991
https://www.homemadetools.net/forum/...193#post115877
https://www.homemadetools.net/forum/...2417#post96268
https://www.homemadetools.net/forum/...171#post138360
