The Plantronics SupraPlus Dynamic headsets leverage the proven design of the HW261N to set new standards in comfort, reliability and audio quality. The dynamic noise-canceling microphones enable clear, uninterrupted communications in mission critical applications. The over-the-head design offers a stable fit for extended wear. Circumaural ear-cushions (sold separately) are also available. Models & Part Numbers: SDS 2491-01 – P/N 92491-01 (Binaural headset with Supra Quick Disconnect) SDS 2491-02 – P/N 92491-02 (Binaural headset with H series Quick Disconnect) SDS 2610-01 – P/N 92610-01 (Binaural headset with TA6M Quick Disconnect) P/N 83195-01 (Circumaural ear-cushion kit for use in noisy environment)