Feature: 1. Non contact design, it can accurately test the speed of the object without contact, to ensure your safety, and carry out industrial testing. 2. LCD digital display, it can clearly display the measured speed on the large screen, helping you to better measure and record, and the performance is stable. 3. Storage function, it supports storage of the last, minimum and maximum readings, which can help you enter data better when you are inconvenient to record. 4. With auto zero function, it can automatically zero itself, help adjust the accuracy in multiple tests to maintain the correctness of the data. 5. Wide measurement range, wide range and high resolution, automatic and manual measurement optional data recording and recall (60 groups). Specification: Item Type: Tachometer Material: ABS Model: DT6685 Measuring Range: 2.5-99999RPM Resolution: 2.5~999.9RPM: 0.1RPM; 1000~99,999 RPM: 1RPM Accuracy: ±0.02%+1digtal Measuring Distance: 50-500mm / 2-19.7in Response Time: 0.5s (Above 120rpm) Operating Environment Temperature: 0-50℃ (32-122℉) Operating Environment Humidity: 10-90%RH Storage Temperature: -10-60℃(14-140℉) Storage Humidity: 10-75%RH Battery: 9V 6F22 Square Battery (Battery Not Included). Package List: 1 x Tachometer (Battery Not Included)3 x Reflective Strip1 x Manual Note: 1. Do not aim the laser pointer at your eyes, and do not directly observe the beam or indirectly observe the reflective surface. It is recommended to wear safety glasses.2. Do not use lasers near explosive gases or other potentially explosive areas.