... 88.1~-107.9MHz) selection, digital display mirror display frequency, RF output stably, more frequency for selection, without interference problem.8 ... Bluetooth version: V2.0 and A2DP 2, Working voltage: 12 to 24V DC 3, Frequency: 2.4GHz 4, Battery capacity: 1,700mAh 5 ... , Standby time: 120 hours 6, Earphone battery capacity: 60mAh 7, Earphone working time: 2 hours ...