Display: 5 digits 18mm(0.6")Yellow green backlight LCD Accuracy: ±(0.05%+1 digit) Sampling Time: 0.5 sec(over 120RPM) Range Select: Auto - Ranging Memory: Last value,Max. Value,Min.value Can store 96s data Power Consumption: Approx 55mA Time Base: 6MHz Quartz crystal Detecting Distance: 50mm to 500mm Measuring Range: PHOTO TACH 2.5 to 99999RPM CONTACT TACH 0.5 to 19,999RPM Surface speed(m/min) 0.05 to 1,999.9(m/min) Resolution: PHOTO TACH: 0.1RPM(2.5 to 999.9RPM) 1RPM(over 1000RPM) CONTACT TACH: 0.1RPM(0.5 to 999.9RPM) 1RPM(over 1000RPM) Surface speed(m/min) 0.01m/min(0.05 to 99.99m/min) 0.1m/min(over 100m/min) Power: 4X1.5V AA Size Battery or to external DC 6V Regulated power supply