Top of the gauges are Starrett, Brown & Sharp. Which I have both, plus a cheaper CDI. All are 1 inch travel. You can get cheaper gauges that won't break the bank. A good way to measure rotor run out. Remove the tire, remove the rotor. Clean the mating surface of the hub and rotor to remove any dirt, etc. Install the rotor and lugs. Torque the lug nuts. The best place to mount the gauge base is on the steering knuckle. But because it's aluminum. You have to clamp it into place. Can't use a magnet base. You can get the gauge at AutoZone, Advanced Auto etc.
Google
https://www.google.com/search?q=meas...hrome&ie=UTF-8