This is a pressed steel knock off of the APCO cast iron gauge I posted on a previous accessory of the day thread.
I run this on our 27 speedster and don't have to worry about a visible glass site gauge breaking and frying the engine.
I remember back several years ago Aaron Griffey showed me the engine of some period high end car that had a float system built into the engine, can't remember what car it was, pakard,lincoln,caddy ??
My 1915 Maxwell model 25 has a cork float in the oil pan. They were trying to compete with the model T.