Sennheiser Set 100 TV Sound Amplifier System with Accessory Jack WEST-SET100JThe Set 100 system by Sennheiser can be used while watching TV, or at hundreds of specially equipped cinemas, theaters, workshop sites, and museums across the country. The sound is clear and direct with no distracting background noise. A high quality audio signal is transmitted on the 95kHz infrared frequency to the receiver. The transmitter easily connects to the audio output jacks of VCRs, most TVs and compatible audible sources.Two year warranty.This model has an output jack on the receiver which allows it to be used with hearing instrument accessories such as induction neckloops, silhouettes, and direct audio input.* It is recommended you purchase an additional battery (NCI-PLS100H) so you always have a fully-charged battery available.NOTE: Not suitable for use with plasma TV screens or in rooms where fluorescent lights are in use.What is an IR (infrared) system?IR, or infrared systems, transmit sound via