All the advantages of the H91 model plus an exclusive noise-cancelling microphone technology which reduces the transmission of noise from the workplace. Noise-canceling microphone Single ear cushion model provides clear sound quality and comfort for all-day use. SES (Sound Enhancement System) tone control switch Lightweight Supports SoundGuard Plus and Call Clarity technologies for superior sound Clear, adjustable voice tube Click-stop headband and turret 10' cable with Quick Disconnect option Headband pad option Adjustable clothing clip H91N: EncoreNC Monaural Headset H91N H91 Encore Monaural Headset Headset Loracomm Plantronics H91N: EncoreNC Monaural Headset