Features NON CONTACT MEASUREMENT: For infrared non contact measurement, press and hold the TEST button for more than 2 seconds, the rotation speed measurement function will be turned on, the front end will emit a red laser, and then refer to the reflective belt o DATA LOCKABLE: The maximum value, minimum value, average value and real time value in the measurement process can be locked. Convenient for you to use and monitor. THRESHOLD SETTABLE: The alarm threshold can be set. When the measurement is higher or lower than the set threshold value, the red background light on the screen will be on for a long time and the measured value will flash as an alarm prompt. ABS MATERIAL: Made of premium ABS material, the meter is wear resistant, scratch and impact resistant, ensures a long term use. EASY CARRYING: Comes with a cloth bag, the meter is convenient and easy for you to store and carry for convenient use. Specification: Item Type: Digital Tachometer Material: ABS Color: Black Measuring Range: 2.5RPM to 999999RPM (rpm per min) Resolution: 2.5RPM to 999RPM (0.1RPM); Above 1000 RPM (1 RPM) Accuracy: ± (0.05% Reading, 1 word) Speed Display: Six digit display, maximum 999999 Measuring Effective Distance: Approx. 50 to 500mm / 1.97 to 19.69in Sampling Time: 0.8 Seconds (above 60 rpm per min) Automatic Shutdown: 10 Minutes (can be closed manually) Operating Environment: - 10 to 50 ℃, maximum 80% relative humidity; Indoor altitude less than Approx. 2000m / 6561.7ft Storage Environment: - 10 to 50 ℃, maximum 70% relative humidity (take out the battery) Display Size: Approx. 37 x 41mm / 1.46 x 1.61in Battery: 1.5 AAA battery x 3 (without battery) Package List: 1 x Digital Tachometer  3 x Reflective Paper 1 x Cloth Bag  1 x Manual  Package List 1 x Digital Tachometer 2 x Reflective Paper 1 x Cloth Bag 1 x Manual