The Plantronics CS50 wireless headset system with HL10 and Online Indicator is the ultimate headset bundle for your office. You'll have the wireless freedom to answer/end telephone calls up to 350 feet from your CS50 headset. In addition, a red light will illuminate on the Online Indicator every time you get on a phone call. This lets others around you know not to disturb and ultimately reduces interruptions that someone would otherwise start talking to you! The Plantronics CS50 also comes included with a headband and ear hook for you to choose the perfect wearing style that best fits your comfort. Lastly, the Plantronics CS50 is compatible with 98% of corded desk phones. Whether you have Cisco, Polycom, Avaya, Shoretel, Mitel, Nortel and many others, the CS50 will work.