I was cleaning out my old toolbox from my days as a gas pump service technician. I found this in the bottom. An old timer at the company gave this to me just before he retired. This is a quick go/no-go tester to see if a nozzle was for leaded/diesel, or the new unleaded nozzles. He told me in the transition period, there was a lot of confusion because the unleaded nozzles have a smaller spout than the standard leaded nozzles so the old nozzles would not fit in an unleaded car. They used these as keychains for their service vehicles, and would use them frequently out in the field to spot check that they had the correct new nozzles for unleaded.
