One of the key features of this magnetic field detector can be to detect magnetic field that are not visible, allowing it to be used in areas where visibility is limited. Mainly used for testing TV, computer, microwave oven, low-frequency home appliances, EMF tester, etc. Features -Color:Black-Material:ABS-Size:15.00X5.50X3.00cm/5.89X2.16X1.18in-Power supply: 1 X 9V battery (not included)-There are 5 LEDs, each representing a field strength range as follows:Dark Green - "normal" area - normal background magnetic field. 0 to 1.5 MGGreen - "low" zone - low level magnetic field. 1.5 to 2.5 MGYellow - "Warning" area - medium magnetic field. 2.5 to 10 MGOrange - "high" zone - high magnetic field. 10 to 20 MGRed - "Warning" zone - extremely high magnetic field. 20+ MG- The EMF tester tool helps measure electromagnetic fields to identify radiation for you.- The magnetic field detector is an electronic device that measures the strength of electromagnetic fields.- The emf meter enables users to determine the extent to which to limit exposure, both useful and practical for home use.- Magnetic field detector is a portable tool for detecting magnetic field that cannot be seen or touched, an essential tool for many industries.- The emf meter can be applied for testing TV, microwave oven, refrigerator, computer, cell towers, etc.Package list: 1 x meter