My Vox came with the 2-piece charger, where the prongs can be detached and replaced with ones to fit foreign receptacles. It will take up to 250 vac. The cord does not detach from the charger. It looks just like this Blackberry charger.
The packaging was designed to hold the parts separately. No doubt this was the charger supplied initially because it would satisfy different world markets by just substituting different prongs. Now, Kobo probably ships dedicated one-piece chargers to different countries because it's cheaper.