Features: It features sensitivity for accurate measurement. With average or maxi readings, 0 resets, low battery indication, buzzer switchs. Large and backlit screen is clear and easy for viewing, the radiation value can be lock for clearly view. Testing TV, computer, printer, microwave oven, refrigerator, cellphone tower, low frequency electrical appliance, etc. The EMF meter can test the electric field and the magnetic field radiation, 5 LED indicators represent different radiation values. Specifications: Material: ABS Range: 0-20+mG±5% Application: 50/60Hz Frequency Monitoring Power Supply Mode: Dry Battery 9V 6F22(Shipping WITHOUT Battery) Light Color: Dark Green: 0 to 1.5 milligauss Green: 1.5 to 2.5 milligauss Yellow: 2.5 to 10 milligauss Orange: 10 to 20 milligauss Red: 20+ milligauss Size: Approx. 150x55x30mm/5.91x2.17x1.18in Package Includes: 1x Electromagnetic Radiation Tester note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.