Additional Details ------------------------------ Bullet point: RJ9 connectivity to Yealink IP phones, including T19(P) E2/T21(P) E2/T23P/T23G/T27G/T29G/T30/T30P/T31/T31P/T31G/T33P/T33G/T40P/T40G/T41S/T42S/T46S/T48S/T42U/T43U/T46U/T48U/T53/T53W/T54W/T57W/T58A/VP59/T41S SFB/T42S SFB/T46S SFB/T48S SFB/T55A SFB/T56A SFB/T58A SFB/MP56 Product description: Perfectly Compatible with Yealink Phones Runs right out of the box, a QD to RJ9 plug-and-play setup makes the connectivity to Yealink IP phones at ease. The phones can automatically optimize acoustic parameters for your YHS34/YHS34 Lite. Perfect match with Yealink desk phones gives you optimized audio quality. Ultra Lightweight Design 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. The extremely lightweight design enables all-day wearing comfortable without pressure. High-Quality 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 conversation with reduced background noise. General Headset cable length: 0.9m QD to RJ9 cable length: 1.2m Color: Black Storage temperature: -30 C to +70 C Operating temperature: -10 C to +50 C Microphone Microphone type: Uni-Directional ECM Microphone frequency response range: 100 Hz-8 kHz Microphone bandwidth: Wideband Microphone Sensitivity: -44.0 dB re. 1 V/Pa Speaker Speaker size: 28mm Speaker sensitivity: 93 dB SPL @ 1 kHz Speaker Frequency response range: 20 Hz-20 kHz Speaker impedance: 32?, @ 1.0 kHz Speaker input power: max 10 mW Speaker bandwidth: Wideband