Now I have the TNC tach it looks very good. Going flying tomorrow. I will give a report after the flying session.

Well I went flying and here are my opinion of the TNC Tachometer

I have bumped my hands and fingers multi times in the past two years and I am getting uneasy having to get real close to a rotating prop. The tach I had, (a red one) needed to be held within about two inches of the prop on a hazy or cloudy day to get a reading and even then the reading was not stable and it bounced all over the place.
I grew up working on engines (auto and airplanes) and I depend on a tach a lot to tell me what the engine is doing.

I checked about 5 different engines Friday and Here are the results.

1. I did not need to get the tach within 12" of the prop.

2. The readings were always stable.

3. The Tachometer has a good quality thick case.

Some of the reading were taken from more than 24" away. This just feel a lot safer to me and always getting a stable meaningful
reading was what I was looking for to understand what the engine was doing.