|Even larger boat anode.|
This sacrificial anode is getting into the "really large" size range at 13 pounds. It is helpfully stamped "do not paint" because of course if you did paint it, it would no longer be in electrical contact with the water around it, and therefore it could not perform its duty, which is to be corroded and eaten away instead of the iron ships hull it is protecting.
Source: eBay seller precision-marine
Contributor: Theodore Gray
Acquired: 17 November, 2003