The short answer is yes.
Capsules charge off USB power and draw up to 500mA at 5V, if it is available. A source with more power will not force more into the capsule, it will only take what it wants, so you can plug your capsules into ANY compliant USB power source with no worries, regardless of its output. This includes laptop USB jacks, apple or android usb-wall adaptors, portable USB power banks, solar chargers, etc.
Some bluetooth headsets or other very low power devices come with USB chargers that put out less than 500mA. These might charge your capsule more slowly or not at all, but will not damage them or the charger. Most USB wall adaptors will run off of 90-250v 50/60hz and can be plugged in to any country’s wall outlets.
However we recommend you check the voltage rating on your wall adaptor for compatibility with whatever wall source you are using :)
You can find dual USB wall adaptors on our website here: http://www.flowtoys.com/dual-usb-wall-adaptor/
If you have any questions, please feel free to contact us!