Bluetooth cable. Features: Transform your wired headphones to wireless. RC-BT unitlizes the Qualcomm CSR8645 Bluetooth 4.1 chips, which supports the aptX, AAC and SBC audio codecs to ensure your get the best out of your music. Three-button multi-function in-line control center. Seamlessly take phone calls and control media playback with integrated microphone and remote. Micro-Miniature Coaxial (MMCX) connectors compatible with FiiO F9/FH1/F9PRO and other MMCX earphones like Shure, Westone or JVC. Transmission distance is abour 20 meters at open area. Battery capacity is 120 mAh. Battery life: about 10 hours. Charging time: less than 2 hours.