The Listen Performance FM System Package works in theatres/cinemas, schools/universities, auditoriums and meeting rooms. The Performance Package comes with everything needed to specify, install and operate a wireless audio package. For places of worship, the Listen 72MHz system is recommended. The Listen 216MHz system is recommended for stadiums/arenas. Limited Lifetime Manufacturer's Warranty. System includes: 1-Stationary transmitter with dipole antenna 1-rack mount bracket 4-Display receivers with batteries 4-Ear speakers 1-ALD window decal kit What is an FM system? FM systems transmit sound via radio waves (frequency modulation) from the speaker's microphone to the listener's portable receiver. Please allow 2-3 weeks delivery for this item.