Four cordless headphones with transmitter are included in the set, along with a storage rack! The rack will hold up to six headphones. Four different VHF/FM frequencies from which to choose. Four different, color-coded groups can work in the same room simultaneously. This cordless system easily interfaces with: Multimedia computers, Personal stereos, Compact disc players, Cassette recorders, CD ROM, Record players, TV monitors, Public address systems, andVCRs.