Plantronics CS50-USB Wireless Office Headset System It s the first wireless headset for VoIP applications with remote call detection and answer/end capability via PerSonoCall software. This convenient 900MHz wireless headset for VoIP applications lets you take the conversation wherever you go with remarkable range and sound quality for crystal clear communications for PC softphone users. Instant USB connectivity for quick setup. Leave Your Desk Without Leaving Your Calls BehindSuperior Sound Quality and Hands-Free ConvenienceNoise-canceling microphone filters out background noiseUp to eight hours talk time per battery chargeRoam up to 300 feet from your office phoneRemote ring detectionCall control at your finger tips: call answer/end, volume +/-Convertible: over-the-ear, over-the-head or optional neckband for behind-the-head900MHz frequency for clear, private, secure conversations