Unique display where characters reverse direction depending on measurement mode you are in. Large 0.4 in. (5 digit) LCD display. Microprocessor based with quartz crystal oscillator to maintain high accuracy. Tachometer memory stores last, max and min readings. Provides wide RPM (photo and contact) and Linear Surface Speed (contact) measurements. Accurate to 0.05 percent with max resolution of 0.1 rpm in either photo or contact mode. Complete with tips and wheel for rpm or linear surface speed, four 1.5V AA batteries, reflective tape and carrying case.