Includes master station & various headset stations. Depending on application. Noise attenuating headsets fit under fireman helmet systems. Easy layout design making it an exceptionally versatile and quick system to install. Durability and performance is guaranteed by using metal housings, military standard plugs & jacks, and EMI/RFI shielded cable assemblies. Standard unit has 6 headset station inputs, but can be expanded up to a maximum of 10. Radio/Power input jack with a 10' cable assembly included.