Qudo QDPRANCBK Instruction Manual page 7

Charging
Charging
Airline Adaptor
The airline adaptor can only be used on the aircraft.
Plug the airline adaptor into the connector of the video player on the plane, then connect the
headphone with the Adaptor by audio cable.
Before using the headphone for the first time, charge it for at least
two hours
Low battery alert
When battery voltage less than 3.3V, the Headphone will be
warning and have tone speak out from speaker.
Charging
red light on
Full charge
light off
7/8
Plug micro-USB cable
into computer's USB port
Plug micro-USB cable
into USB wall charger