tiny tach and clones on outboards

[jacoboregon]

Have any of you used the 'tiny tach' or one of the clones on your outboard? I'm considering getting one to put on my pull-start tohatsu 40hp to see how it's running in regard to rpm's at wot. I'm wondering if anyone has experience with accuracy and longevity.

I understand it is only 'water resistant' so will need to be mounted as dry as possible.