Detects and confirms radio frequency and/or infrared emission from key fobs and remote controls. Helps diagnose faults quickly and easily without the need to dismantle the fob, remote or vehicle. Magnetic backing sticks to the side of any ferrous surface making distance test of transmitter a possibility. Suitable for a wide variety of vehicle and electronic/electrical applications. Suitable for detecting new BMW frequencies. Powered by 9V battery (not included).