Works well in my drill press.

Hard for installing but working good .

Originally posted this on the RED unit, probably won't get a "confirmed purchase" tag on it. The blue one is the one I purchased. For some reason the pics arn't showing on the other post??
Saw a lot of questions on this tach so I thought I would review it and hopefully answer some of the many questions but before I get too far along remember the old adage "You get what you pay for" most of the time. This is a very inexpensive device, something you could pay several $100 for if it were a laboratory grade piece of electronics so keep that in mind if you buy one.
The Review:
I needed an RPM meter for a grinder I am building on the CHEAP. It will be a 2x72 belt grinder made mainly from a couple of used treadmills. I am using the treadmill motor to drive the belt and needed to know the speed of the belt so I figured a tach on the motor shaft would give me a good idea of belt speed. Bought this inexpensive kit and am very well pleased with it. If it had had some wiring instructions(pic attached) I would have given it 5 stars. I deducted a star for having to figure it out myself. I am powering it with a 9VDC AC-DC converter that plugs into a wall receptacle, one of the little devices that power our calculators and laptops, charge our phones etc. They are commonly referred to as "WALL WARTS". I have about 20 of the things thrown in a box form over the years. This one is "rated" at 9VDC at 210ma(mili amps). Some of the pics show it hooked up to two meters and the tach kit. If you look at the meters closely you will see that the digital is reading 11.87VDC, the no-load voltage for this WW(wall-wart) is 13.2DC by my measurement. Electronics folks will understand this but for the non-electronics folks, when the power supply is loaded the voltage drops, per the rating data if it had a 210ma load it would drop to 9VDC. That brings me to the actual load, note the old analog meter, it is set on the 60mili amp scale and is reading about half scale or about 30mili amps. That means that the tach kit is only loading the WW to ~30ma there by only dropping the output voltage to the 11.87VDC Based on this the minimum rated WW could be as low as 9VDC at 50ma, a very small WW indeed. The take away here is that most any 6-9VDC WW would do the job. I am saying 6-9 and not 8-15 because of the low loading effect the tack has on the WW power supply. I say start with 6 because I have four 6VDC WWs and all of them show a no-load voltage of 8VDC or more. One of my 12VDC WWs has a no load voltage of 17.8VDC. You would not want to apply that much voltage to this unit. Check out the pics for answers to other questions such as how to wire it up.
Finally I highly recommend this and the similar other color tachs for non-critical applications. Great inexpensive hobby stuff.

Edit: For some reason all the pics arn't showing for this post although I see the thumbnails in this editing session. They are however showing in the the nearly identical post for the RED version of this tach. Check it out if you donot see the wiring diagram in this post.

Works perfectly. Quality product.

Worked good.