UT373 is a reliable digital non-contact tachometer used to measure rotation speed of motors and other machines.This device is able to display results in RPM or revolution count.UT373 is able to safely measure rotational objects through a non-intrusive method.1. Auto range2. Up to 99999 display; overload diaplay, "OL"3. RPM measurement and revolution count:RPM measurement-Range: 10.0-9999.9RPM / Resolution: 0.1/ Accuracy:+/-(0.04%+2)RPM measurement-Range: 10000-99999RPM/ Resolution: 1/ Accuracy:+/-(0.04%+2)Counting measurement-Range: 0-99999 counts/ Resolution: 1/ Accuracy:+/-14. Max/Min, data hold5. Singal trigger/laser-on indication6. Low battery/auto power off indication7. LCD backlightRefresh rate:1s to 7s (greater than 120rpm for 1s)Sensor type:Photodiode and laser-tubeTarget distance:50mm-200mmMeasuring angle:+/-30degree from perpendicularDrop test:1mPower supply: 3 x 1.5v AA battery (not included)colour:Red+grayMaterial:ABSsize:120 x 53 x 34mmPackage Contents:1 x UT373 Mini Tachometer (not including battery)2 x Reflective stripOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.