Feature: Hand Free Driving 24Hrs Comfort Designed for business and driving CSR Bluetooth chip (V4.1 ) Bluetooth phone Bluetooth wireless music transmission Answering/ending a call Arc line,Rotatable design, ultra light weight for easy carrying Technical parameters: Calling time: 4 hours Music: 4 hours Standby time: ≥250 hours Charging time 1-2hrs (DC5V) Speaker: 16Ω SNR: -90 dB Distortion: ≤ 0.1% Working Current: 30 mA File format: MP3 / WAV Transmission distance: ≤ 10 m Li-Battery capacity: 3.7V 80MAH Standby current: <500uA Package include: 1xE5 headphone 1x USB charging cable