Adapters
3-pin UK-style often required
While your devices will probably adapt to the Electricity readily enough, you may need to be equipped to deal with the outlets which take British-style, three-pin rectangular plugs (Type G).
Higher-end hotels usually have outlets with built-in plug adaptors to fit foreign prongs. More moderate hotels often have adapters you can borrow for free.
Otherwise pack one, or pick one up one cheaply once in Hong Kong.