Features: Fast and accurate contact RPM and surface speed measurements of rotating objects Memory function saves maximum,minimum and last rpm readings, can store 96s data Automatically switch the detect range 5 digits 18mm (0.6") White backlight LCD, high visible and backlight display Specifications: Accuracy: ¡À(0.05%+1 digit) Sampling Time: 0.5sec(over 120RPM) Range Select: Auto-Ranging Power Consumption: 45mA Time Base: 6MHz Quartz Crystal Time Base Accuracy: 10*10-6(0 to 50 Degrees C) Measuring Range: Contact Tach: 0.5 to 19,999RPM Surface Speed: 0.05 to 1,999,9m/min Resolution: Contact Tach: 0.1RPM(0.5 to 999.9RPM) 1RPM(over 1,000RPM) Surface speed: 0.01m/min(0.05 to 99.99m/min) 0.1m/min(over 100m/min) Power Supply: 4*1.5V AA Battery (not included) SKU: X1IN10160 Package includes: 1 * Tachometer 1 * User Manual