Protmex Digital Tachometer, 50-19999 RPM Contact Tachometer, 100 Groups Data Store Handheld Speed Meter with Backlight, Max/Min/AVG RPM Rotation Speed Gauge, PT6208A (Batteries Included)

Surprisingly easy to use, gives steady readings when used to measure electric motor RPMs.

Would not change wheel size setting. Followed instructions and the meter would not change from 0.1m Perimeter wheel to 6". According to the manual, you cannot measure in ft/min with the 0.1m wheel. They spent more on the look of the product than the functionality. Cheap product...do not purchase.

Used it to test generator speed. Worked great

This unit is fairly accurate, although not intuitive, especially when it comes to determining which wheel is what. The display lets you select between several wheel sizes, one of which does not come with the kit. The power doesn't stay on long, which saves battery, but is a pain because it doesn't hold your mode when it powers itself off. Maybe there's a setting, but I have yet to find it.

Had to read instruction to figure it about after that worked great

The device works, however the instructions are horrible and I could not find videos online on how to make this device work. I would not recommend this purchase if you need something to simply work out of the box. It took about a day of trial and error to get it working.

Did not work at all. In contact mode no RPM seen by hand. Tried and on machine, no reading. Holding measure button does nothing but lock up the unit requiring the batteries to be pulled to turn off. Instruction sheet horribly wrong. This is pure junk.

The feet / Minute and other modes do not work

I bought this to calibrate a treadmill but it seems to not work at all, the reading has never increased above 0 with any attachment at any RPM.