Wireless headphones wihte a line of sight range up to 100m.
Note that these completely use the 863 - 865 MHz Frequency range, therefore they cannot be used simultaneously with radio mics or wireless in ear monitors in that operate in that band.
Audio input is by stereo 3.5mm mini Jack, although adapters to 6.35mm jack and 2x RCA (Phono) plugs are included.