Please Note:Not included battery 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. This portable device is able to safely measure rotational objects through a non-intrusive method. Features 1. Auto range 2. Up to 99999 display; overload diaplay, "OL" 3. RPM measurement and revolution count 4. Max/Min, data hold 5. Singal trigger/laser-on indication 6. Low battery/auto power off indication 7. LCD backlight Packing list: 1* Laser Tachometer 1*Instruction manual