The spark plug / Gen .. is for a DELCO light plant. I ran across an article where the man responsible for the DELCO systems for farmsteads, etc. explained that the customers would mess things up, so the wrenches were clearly marked to try to encourage end users to employ the correct wrench for the job at hand. Sadly, I lost the link to that article during a "lockup" of my underpowered / overworked laptop. A copy of that article with a set of those wrenches would be a nice educational display and reminder that the effort to electrify farmsteads had a long history before government subsidy / public power was established, and put DELCO & similar systems out of the running for the most part. We had a neighbor who did not have the money to extend the power line that last half mile, and only had a WINCHARGER & small 32 volt DC system with batteries that they used to run a radio and a couple of dim light bulbs. They also had no running water, etc -- a very 1930s existence well into the mid-1960s when their son got enough money to fix his parents place up a bit.
