The Eartec TCS-4000PL Wired Intercom is designed for broadcast communication. The system consists of a power station and four Eartec Proline Headsets. Dual and Single-Eared Models This kit comes with both single- and dual-ear ProLine headsets. Volume Controls ProLine headsets feature a compact amplifier and volume control built into the ear cups. This eliminates beltpacks and reduces interconnecting XLR connectors. Auto-Muting Boom The microphone of the ProLine includes Auto Mute technology, which allows users to easily mute their mic simply by positing the boom straight up.