EM0328 is the Microwave Leakage Detector. · No battery needed, compact and easy to use, ... read.· Frequency range: 3MHz to 3GHz· Applicable to mobile phone, microwave oven,mini camera using electromagnetic field,etc.·Range: 0-10mW ... 5 mW/cm (Safety)·Red Zone : Over 5mW/cm (Dangerous) Microwave Leakage Detector