Perfectly compatible with Yealink Phones Runs right out of box, a QD to RJ9 plug-and-play setup makes the connectivity to Yealink IP phones. The phones can automatically optimizes acoustic parameters for your YHS34/YHS34 Lite. Perfect match with Yealink desk phones give you optimized audio quality. Unparallel Audio Experience Made for calls, YHS34/YHS34 Lite is kitted out with a high signal-to-noise ratio speaker and independent cavity design. The passive noise cancellation creates a richer and clearer conversations with reduced background noise. Ultra-lightweight, All Day Wearing Comfort Built for comfort with soft ear cushions and ultra-lightweight materials, the YHS34/ YHS34 Lite is 10%~30% lighter than other headsets in the same range. Its ergonomic design makes this headset comfortable enough for long conference calls and all day use.