Review on Fowler 74-150-005 Electronic Rotor Gauge: Precision Measuring Tool for Rotors by Jeff Grindley

This is a precision instrument. It costs like one (compared to the $40 alternative) and looks the same. But the photos of the product are of poor quality (seriously, is the whole sales team asleep?) so I've added a few. It's a battery cover, and it's just round. You move the jaw by moving the display section along the shaft. It moves very smoothly and you get the feel of a precision instrument. The zero button is probably useless for brakes, but might be useful if you want to use it as a caliper in some other application: you can use it to get negative offset readings. The zero position is retained when switched off. Therefore, its main value lies in the elimination of zero error (i.e. ensuring that the reading is zero with the jaws closed). The small gray rectangular plastic cover at the top of the display area exposes some sort of electrical contact, possibly for testing/updating the firmware at the factory, but not relevant to the user. The anvils are well designed. The repeat accuracy is approx. 0.01 mm. The sensors are 2.7 cm (just over an inch) from the rod. I would have liked a longer brake rotor reach to shave off width in more places, although it would have made getting in and out between the rotor and rim more difficult. I'm not giving a star for that, overall this is a better quality product than I expected. Comes in a black case (thin and cheap but adequate) with foam padding to match the feel of a precision instrument. Uses TWO 3V lithium batteries (CR2032), although only one is used at a time. Despite this packaging, my product arrived with pursed lips - it's not clear how that happened because even if I try a little to reproduce it, it won't work. Where it was made is not specified. Feels German. Fowler is based in Newton, Massachusetts and the instructions are written in easy-to-read English.