These are actually combined photo/contact tachometers. They have a range of 0.5 - 100,000 RPM and come with a carry case.
Lutron DT2236 digital tachometers also include a unique reversing 5 digit display and a function to recall last value, maximum and minimum.
Further features of Lutron DT2236 digital tachometers:
- Light source is IR LED for use at close range - for long range use DT 1236L laser version
- Using an exclusive one chip LSI circuit, the DT2236 measures linear velocity in m/min, ft/min, as well as RPM from 0.5 to 100,000.
- The instrument auto ranges to give resolution up to 0.01 m/min & 0.1 RPM.