1、Fast Accurate Measurement: Provides fast and accurate RPM (revolutions per min) measurements of rotating objects. 2、Automatic Memory Function: Maximum value, minimum value, and the last measured value up to 96 sets of measurement data. 3、Features: High accuracy ±(0.05%+1digital), range selection is automatic range, sampling time is 0.8m/s. 4、Multi Mode: 5 digit super long range, multi parameter mode is optional, time base adopts quartz oscillator. 5、Easily Use: Can be measured close to the object, strong anti interference, 80 cm distance measurement. 1 x Digital Tachometer2 x Speed Reflector1 x User Manual Item Type:Digital TachometerMaterial: ABSPurpose: For Speed Measurement of Tire Bearing BladesBattery: 1.5v 4 x AA(Not Included)Measuring Range: Photo TACH 2.5 to 99,999RPM 0.5 to 19.999RPMSurface Speed: (m/min.) 0.05 to 1. 999.9 (m/min.)Resolution: Photo Speed 0.1 Revolutions ( 2.5 to 999.9RPM)1rpm (over 1000RPM)Speed Mode: 0.1RPM ( 0.5 to 999.9RPM)1RPM (over 1000RPM)Surface Speed: (m/min) 0.01 m/min. ( 0.05 to 99.99m/min) 0.1 m/min (above 100m/min)Accuracy: ±( 0.05%+1 Digit)Sampling Time: 0.8 M/s (over 60 RPM)Test Range Selection: AutomaticSensing Distance: 50 to 500 mm/2 to 20 Inches (photo)Time Base: Quartz