EMRSS MG-300 Magnetic Field Meter EMF Meter is used to measure electromagnetic fields of extremely low frequency (ELF0 of 30 to 300Hz Display: 3-1/2 digits LCD, maximum reading 1999.Range: 200/2000 mG,20/200T. Resolution: 0.1/1 mG or 0.01/0.1 T. Frequency response: 30Hz to 300Hz. Accuracy:  (2.5%+6dgt) at 50Hz/60Hz. Over load: LCD display OL. Rate: 2.5 times per second.Battery: 9V NEDA 1604, IEC 6F22 or JIS 006P. Approximate 100 hours.