Here is my Dobbie-Mcinnes no 2 engine indicator, in its original box, with all its original springs, rulers and cards, still has original key too, hope you like it.

Pete H.

it does a lot to be honest, i think the main job was to measure horsepower, but also they will tell you (if you know how to use them) if the valves are working as they should, and to check if the engine is running as it should, i myself have no idea how you would get it to tell you this, it is a very nice piece though, they made one for ships, and they sell for £300, but i have never seen one for combustion engines sell, so i am a little unsure of value?