How late were these given out?
Part of a tool kit?
Do todays CAT natural gas engines have spark plugs like todays car engines?

gauges like that were still around in the 60s just not cat branded i know someone who has one like that.

I just bought 1 off fleabay. How late was any pony starting engine offered?

Starting engines were an option to the end of year 1969.

I will say UNcommon. First one I have seen. I hope shipping was not expensive LOL. JM

The only one of these I ever saw was in a toolbox on a Cat 30 that sold about 20 years ago. Most folks wouldn't know what the C T stood for. Most of the give aways were cheaply made and the wire type was usually sandwiched between two pieces of tin. I preferred the ramp type as one just slides the plug around until it stops and read the gap number.
I would bet there are not a lot of these in circulation!!

I think they came out ww2. not sure though. you think giveaway?? i was hoping later toolkit item. C.T. Co. is on most serial number tags thanks.

AG-M I think you are right they look pretty good for a giveaway. They look like they may have been a giveaway if you bought a Cat!! The guy that had the Cat 30 did not have any other Cats and of course no ponies. I wonder if the gauge came with the Cat 30 as the guy never threw any thing away. Maybe some early gas experts could help us out. I would guess they did not come out in WWII as there was such a demand for AL for aircraft.

I don't think its made of aluminum, haven't received mine yet. I think they were cadmium plated.

very common and could even be a give away. many many like that around here and i don't think C.T. stands cor caterpillar either ???   probably a product of the long gone era of the J.A.Pan company.