2-in-1 wearing style the D 10 Series comes with a 2-in-1 choice of wearing styles with single-sided headband and ear hook. All D 10 headsets fit in to - and can be paired with the same base station. Headsets are for either left or right wearing preference. The sound quality Sennheiser voice clarity. For the best possible communication between caller and listener, Sennheiser Voice Clarity uniquely enhances the most important frequencies and details of the human voice. For the caller, sound is crisper and clearer, allowing them to hear the nuances contained in spoken conversation ? and for the listener, a noise-cancelling microphone sends the clearest signal to improve intelligibility. In combination this results in better, more natural sounding conversations where no important details are lost.