Sennheiser Presence UC (504576) - Dual Connectivity, Single-Sided Bluetooth Headset for Mobile Device & Softphone/PC Connection, with Carrying Case and USB Dongle, Major UC Platform Compatible (Black) Mobile Unified Communications: For professionals who require a consistently excellent communication solution for all Major UC platforms (Cisco, Avaya, IBM, etc.) Improved Flexibility: Connects to two mobile phones, or a cell phone & PC, to allow for seamless transitions between connected bluetooth devices Optimized Speech Clarity: Unique SpeakFocus technology with three digital microphones enhances voice clarity in all sound environments and provides the user with consistently clear sound Advanced Own-Voice Detection Technology: When you are speaking, an own-voice-detector detects your voice and optimizes speech intelligibility as well as reduces background noise for your listener Equipped: Comes included with a Car Charger, USB Charging Cable, USB Dongle, Ear Hook, and Carrying Case, all designed to ensure you are ready, no matter where you are ActiveGard Technology: Featuring patented hearing protection to defend against acoustic shock caused by sudden sound bursts Peace of Mind: With a 2-year warranty on all headsets (including batteries), you never have to worry about the quality of your office headset Extended Talk-time: Presence delivers up to 10 hours call time between charges. Choice of Wearing Styles: Three-in-one wearing solution for maximum comfort and convenience Wind Noise Reduction  WindSafe technology reduces wind noise in outdoor situations