Quantity: One piece Size: 135 × 68 × 25 mm Measuring range: 20 Hz–2000 MHz Display unit: μm/cm² (microwatts/square centimeter) Test error: ±10 μw/cm² (microwatts/square centimeter) Sampling rate: Approximately 5 times/second Operating temperature: 0–40°C Operating humidity: Less than 70% RH Alarm mode: Audible and visual alarm Digital display range: 0–1999 μw/cm² (microwatts/square centimeter); if exceeded, it will be displayed as: 1 Method for detecting high-frequency radiation from cell phones: Turn on the power switch and place it near the phone. In standby mode, the instrument usually does not display a reading. (If the cell phone's radiation level is still above the standard, the phone can essentially be discarded.) Then, use the phone to call the cell phone being tested, and the cell phone's radiation value will be displayed on the detector's screen, accompanied by visual and audible alarms. Because electromagnetic waves are constantly changing, the displayed values may also fluctuate within a certain range. Methods for detecting low-frequency radiation from household appliances: Turn on the power switch and place the front of the instrument facing the target to be measured. If radiation is present, the radiation value will be displayed on the detector's screen, accompanied by visual and audible alarms. Because electromagnetic waves are constantly changing, the figures shown above also change constantly within a certain range. To detect radiation protection products, hold the radiation protection card in your hand and place it between the instrument and the target to be detected. The effect of the radiation protection products can be seen from the change in the displayed value. Test Range: Electromagnetic radiation from lower frequency band electrical equipment such as family rooms, offices, computer rooms, control rooms, high-voltage lines, computers, televisions, copiers, fax machines, cables, Bluetooth wireless systems, monitors, air conditioners, and high-frequency radiation protection products from mobile phones. Electromagnetic radiation test. Precautions: 1. Please turn off the device when not in use to prolong battery life. 2. When an error message appears on the screen, the battery (9V battery) must be replaced immediately. Battery not included Good quality product