Highlights: 1. Detachable battery chip and also it’s replaceable, 4 pieces of battery chips, a real backup for earphones, worry free for durability. 2. More convenient and friendly operation. Battery plug in to power on and search for bluetooth, skip the step needing to press power button for long time to get into pairing mode. 3. An innovation appearance-lighter alike charge case. Small, intact, portable and stylish. It will be a wonderful gift for your father, husband or boyfriend etc. 4. Three frequencies are balanced, crisp highs, clear mids and strong lows, steady sound quality. Specification: Model: Syllable D9X Bluetooth version: V4.2 Supported profiles: HFB/HSP/A2DP/AVRCP Frequency range: 20-20000Hz Sensitivity: 100±3dB Resistance: 32Ω Battery capacity: 38mAh/per piece Charge time: 40minutes for earphone, 1.5-2hours for charge case Music time: 2hours(8hours in total) Compatibility: compatible for any bluetooth device disregard of brands in the main market, as long as it’s bluetooth enabled.