Check the listing for details. Plantronics - CS540 Wireless DECT Headset (Poly) - Single Ear (Mono). Color: Black, Condition: New. Listed at 99.99 USD. Experience the freedom of wireless communication with the Plantronics CS540 Wireless DECT Headset. Designed for convenience, this single earbud headset features an ear-hook form factor that stays secure and comfortable throughout the day. With Bluetooth, USB, and 3.5mm jack connectivity options, you can easily switch between devices and environments. The CS540 is equipped with advanced features such as noise cancellation, a built-in microphone, call functions, and volume control for a superior audio experience. A Microphone Mute Button and Detachable Cable offer added convenience, while wireless charging capability ensures your headset is ready whenever you are. This sleek black headset, with a 6ft cable length, is the perfect companion for busy professionals on the move.