This looks like a stunning little daily 'in the bag' travelling companion! Rather charge through a dedicated device via usb other than swapping out batteries on your cana as a charging device Great for charging from the USB port of your pc or in the car. Like the single 18650 better, but the UM20 is dual and has the same features.
nitecore UM10 Charger
to boost usb charging performance use the following ASUS app: ASUS AI charger
works like a charm, and does pump out more power via USB