JELLICO CT-33 9D surround sound Earphone Material CNC metal back cavity+ABS+TPE+Silicone Frequency Response 20-20K Hz Transmission Power 0dBm, Class II SPL 112dB(1KHz\1Vms) Microphone Sensitivity -43dB±4dB/max2.2KΩ Speaker Impedance 16Ώ Speaker 10mm 6U Function of the line control system Connect/hang up the call, Play/Pause the music,Adjust the volume Plug Size 3.5mm Length 1.2m