Coiled cord lets you take advantage of the full wideband audio that's offered with your compatible phone. Quick Disconnect capability allows you to detach the headset without losing the call. Coiled design easily stretches and retracts to prevent tangling or getting in your way during a call. It is designed for use with the HP EncorePro, DuoPro and TriStar headsets (not included). Compatibility: HP Headset: EncorePro DuoPro TriStar 85R38AA