The Eartec ProLine PS20TCS is a Single Sided Headset with connector for Eartec's TCS Wired Intercom (no beltpack required). ProLine are "Battle Tested" Light Industrial headsets that provide crystal clear voice transmissions across a multitude of industries. They combine specialty electronic components with rugged construction and deluxe padding. The fact that they are affordably priced is just, "icing on the cake"! Eartec manufactures the ProLine with either electret or dynamic microphone elements. This means that they will operate with virtually any intercom in the world. All ProLine headsets feature a specialty noise cancelling microphone that can be worn on left or right side.