Instantly responds to EMF fluctuations and spikes. A 9-volt battery is required. Easy to read LED light scale in dark and sunlight. Portable, easy to use, rugged, reliable and responsive. UV reactive color labels. For paranormal wave research and general EMF detection use. EMF flow meters are often used during and also for personal safety to identify potentially harmful high EMF radiation. Reliability and quality of EMF flow meters in paranormal investigations. This makes the EMF meter a tool for detecting mental activity and finding potentially harmful high EMF levels in the home or work environment. This high-quality magnetic field tester is radiation-proof. The EMF meter is a compact and easy-to-use magnetic field strength meter. The EMF Meter can be used indoors or outdoors to measure any electrical device or power line. There are 5 , each representing a field strength range as follows: Green - "normal" area - normal background magnetic field. 0 to 1.5 milliGauss Green - "low" zone - low level magnetic field. 1.5 to 2.5 milliGauss Yellow - "Warning" area - medium magnetic field. 2.5 to 10 milliGauss Orange - "high" zone - high intensity magnetic field. 10 to 20 milliGauss Red - "Warning" zone - extremely high magnetic field. 20+ milliGauss Power supply:1 X 9V battery (not included) Colour:Black Material:ABS Size:14.3x5.3x2.2cm/5.63x2.09x0.87in Package Contents: 1 * Detector 1 * English user manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.