Accurate and reasonably priced tachometer

[WaterDog16S]

Looking for recomendations on an accurate and reasonably priced tachometer. Since I only work on my stuff, will only use it a couple of times a year. So it doesn't make sense to spend much on it.
I found this Archer A523051 on Amazon and Ebay.
Does anybody have experience with it?
Any and all input will be appreciated.
Thanks.

 

[president]

looks like the old Stihl series tacks!

 

[Thesandman]

I just have the cheap $10 one and it seems to work fine. Rap wire around plug wire and tape to handle bar