Yard force LX PB21 Manuel D'instructions page 10

Instructions
IV. Power Indication
When the charger charges the mobile power supply, or the mobile
power supply charges digital products such as mobile phones, the
power will be displayed, and the LED displays the percentage.
V. Applications
Suitable for most mobile phones, tablets, PC's, cameras, videocameras,
bluetooth and other digital devices with or similar with 5V input.
Connect the device to the power bank by using the charging cable and
turn it on.
List of packaging:
21W Solar Powerbank x 1
Manual x 1
Specified output cable x 1
Warm Prompts
For the difference of connector data and technology, some digital devices
may not compatible with the battery, not for the quality of the battery.