The Triplett Test Equipment Magnetic Field Meter, No. EMF20, is designed to measure extremely low frequency (ELF) electromagnetic fields in numerous applications. The rugged, handheld EMF20 measures ELF electromagnetic fields (30 to 300Hz) produced from electric transmission equipment, air conditioners, refrigerators, fans, and many other appliances that emit electromagnetic fields. According to the company, measurements have a guaranteed ±2.5 percent accuracy, and can be displayed in milligauss (mG) or µTesla (µT). It also has a single axis sensor, max hold function for storing the highest reading, and includes a carrying case.