How do you use Onyx Dual Charger?

How do you use Onyx Dual Charger?

https://www.youtube.com/watch?v=Jui0_xjB0Pw

How do I charge my Onyx battery?

All you have to do is plug the unit into the charger. Push the "on" button and the "on" light will flash until the unit is fully charged. Hope you love yours as much as I love mine. It has great bass outdoors, blow your mind when inside, and will run the full 5 hours on battery.

How do you use a universal charger?

https://www.youtube.com/watch?v=WtunOPJp-Gw