Yealink YHS36-Dual Ip Phone Wideband Ear Rj9 Headset, Wired Headset, Black and silver, QD to RJ9 cable length 1.2m, Microphone bandwidth Wideband, Microphone Sensitivity-44.0 dB re. 1 V/Pa, Speaker sensitivity 93 dB SPL 1 kHz, 60 mV, Speaker impedance 32+/-4.8 1.0 kHz, Speaker input power normal 5 mW, max 10 mW, Speaker bandwidth Wideband. The Yealink YHS36-D is an over-the-head style headset that is made for the office workers, SOHO, or call centre staff. It supports QD (Quick Disconnect) feature and it is compliant with the full range of Yealink enterprise IP phones.