Yealink YHS36-MONO, Mid-level RJ9 headset, Monaural, Runs right out of the box, a QD (Quick Disconnect) to RJ9 plug-and-play setup ensures the connectivity to Yealink Desk phones. Perfect match with Yealink desk phones give you optimized audio quality and more enhanced functions. Noise-Canceling Microphone, Excellent Audio Experience, All Day Wearing Comfort and Universally compatible to work with common calling applications across almost all platforms and operating systems.