Sennheiser  SH230 Monaural Headset with Microphone Patented active Guard technology to safeguard your hearing Easy disconnect Omni-directional microphone Omni-directional microphone with flexible boom arm allowsm for accurate and stable positioning and optimal durability. Ball mounted speaker capsule automatically self adjusts for wearing comfort Active-gard, a patented technology, acts as an automatic control in your headset to instantly lower the volume from acoustic bursts. Detachable headband for easy upgrade to clip on.