Feature:1. Using technologies such as microcomputer (MCU), optoelectronics and semiconductor lasers, it realizes noncontact measurement of speed, and can measure without destroying the measured object.2. Wide measurement range, high resolution, free switching between manual measurement and automatic measurement, can be more suitable for various specific purposes.3. Two gears are adjustable. It has high and low laser power, which greatly facilitates longdistance and shortdistance measurement, and protects the user's eyes from excessive laser brightness.4. Automatically record 50 sets of measurement data, and its sampling interval can be adjusted to meet the measurement needs of different objects.5. Numerical record, it can record the maximum, minimum and average values during the measurement process.Specification:Item Type: TachometerMaterial: PlasticModel: DT2237CDisplay: 5-Digit LCD Display, The Maximum Reading is 99,999.Measuring Range: 2.5 Rpm-99,999 RpmMeasurement Resolution: When the speed is between 2.5 rpm and 999.9 rpm, the resolution is 0.1 rpm; when the speed is greater than 1000 rpm, the resolution is 1 rpm.Measurement Accuracy: (0.05% Measurement Value + 1 Digital)Effective Measuring Distance: Approx.50-500mm / 2-19.7inSampling Rate: 0.5 Seconds (Above 120 Revolutions)Time Base: Quartz CrystalOperating Temperature: 0~ 50Storage Temperature: -20~ 60Power Supply: 1x9V 6F22 Battery (Battery Not Included)Purpose: It is a speedometer for speed measurement..Package List:1 x Tachometer (Battery Not Included)1 x English Manual