It was just a budget cheap'n'nasty made in china from the local parts supply. All I used was the gauge innards and the sensor. The electrical gauge had a bit fatter needle than the original. If I was a bit fussier I'd have found a way to fit the original needle (shaft sizes didn't match), but only the top half of the needle is visable when it is installed and it isn't really very noticable.

The only trap that you can't deduce from the photo is that I had to insulate the gauge face from the two studs of the electrical gauge. The studs on the electrical gauge I used went straight through for the connection terminals on the other side. I insulated the face by screwing it on via a small piece of printed circuit board (with copper removed!)

It was a bit fiddly to make but I was more confident that I could get a good result this way than I would by grafting on another bulb. The added advantage is that - should I ever need to take out or strip down the engine - it is a simple matter to disconnect a wire without damaging anything.