Yes, the Sonicare ProtectiveClean 6100 charges on a plug-in charging base.
#2 Is the Sonicare Protective Clean 6100 dual voltage?
You shouldn't have any issues charging this Sonicare ProtectiveClean 6100 on your travels as long as the voltage of the outlet you're plugging into doesn't exceed 220V. The voltage for this particular Sonicare is 100-220V, but it may require a plug converter in the country you are in.