The Plantronics SupraPlus Dynamic headsets leverage the proven design of the HW251N 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. Cable, connector, and PTT options are available upon request. Models & Part Numbers: SDS 2490-01 – P/N 92490-01 (Monaural headset with Supra Quick Disconnect) SDS 2490-02 – P/N 92490-02 (Monaural headset with H series Quick Disconnect) SDS 2609-01 – P/N 92609-01 (Monaural headset with TA6M Quick Disconnect) P/N 83195-01 (Circumaural ear-cushion kit for use in noisy environment)