This product works as intended. Unfortunately, it wasn't quite what I wanted to do with it. I found that I couldn't get the rubber tabs exactly centered on the flywheel I was trying to measure, so they kept falling off. Not the fault of the product, it just isn't designed for its intended use. On the shaft end with drilled center detent it works great and the linear motion wheel makes it easy to measure linear velocity too. However, for speed checking of small motors, choose an opticalโฆ