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. Singal trigger/laser-on indication Low battery/auto power off indication Is able to safely measure rotational objects through a non-intrusive method. Storage humidity 0-80% RH Speed Range 10-99,999rpm Measurement Count 0-99999 Storage temperature -20 to 60"C Operating temperature 0 to 50"C Operating humidity 0-80% RH Drop test 1m Target distance 50-200mm Working temperature and humidity 0 " C to 50 " C (no more than 80%RH) Items Included Operating Manual Reflective Strips 1.5V AAA - 3pcs Auto range Up to 99999 display; overload diaplay, "OL" Max/Min, data hold