OK, we have to differentiate between Photo-sensitive tachs and Visual (Optical) tachs. ONE type is MUCH safer than the other ones. Safety being the number one concern, photo-sensitive tachs pretty much falls off the list. Notice how the two people that were not argueing about my "personality" only mentioned those two. The other ones are so dangerous that are not even worth mentioning.

As mentioned before, there are two Visual tachs: One is the Miniature Aircraft, and the other is the Model Avionics. One is over $100 and does not reach 3000 rpms. the other is closer to $80 and can reach 3000 rpms.

I might be arrogant, that remains to be seen. But the fact that people come to these forums to have the information given to them is an undeniable fact. And nobody has proven me wrong yet. If the topic starter would have laid out the research he had done, my response would have been a whole lot different. If the question had gone somewhat like this:

"Hey guys, I'm thinking about buying a Tach. I noticed that there are some that are visual, and some use light sensors to calculate rpms. what are the benefits or downfalls of each?

Then the subject would have gone a completely different way.

But his question was so vague, that it seemed like he was looking for a handout. Notice that (other than your input) all through this thread there are only two tachs mentioned. Leading me to believe that he had not done a least bit of research before posting this question here. There are only two tachs worth purchasing, safe and accurate. Take your pick from there. If you want to play with your safety, your selection becomes a little wider.

I would NEVER use a photo-sensitive tach and would never suggest that somebody use one either.

I'm done here. Time to move on.

Rafael