THE BEST OF THREE WORLDS NOISEGARD™ HYBRID ADAPTIVE ANC By constantly monitoring your background environment for noise, Sennheiser's NoiseGard™ hybrid adaptive ANC technology seamlessly adjusts the level of noise reduction in your headset. This unique technology enables you to take control of your sound environment, so you can have a productive, disruption-free workspace. UC CERTIFIED BUSINESS-GRADE COMMUNICATION Business-grade communication voice clarity is key to success in every organization. The MB 660 wireless and wired solution in one deliver a certified, business-grade communication experience, whichever your UC environment might be.SENNHEISER SIGNATURE SOUND Create your own sound with a choice of sound effect modes, to get the best personalized sound for speech, music and entertainment. The MB 660 delivers stereo audio, and CD-quality streaming with aptX® in Sennheiser's renowned high-quality, for your ultimate sound experience. RECLAIM YOUR OFFICE We haven't compromised on a single detail with the MB 660 series. In addition to taking noise cancellation to the next level and delivering the renowned Sennheiser signature sound, the MB 660 Series has been designed to be the ultimate business tool for maximizing your productivity.