“Legitimate” MTR map cards do not exist in Hong Kong.  An online company in China either does or did offer these for sale, and we were very lucky (and grateful) to get this one, mailed to us from inside Hong Kong in 2012 with stamp and postmark–along with major postmark transfer on the front.  We suspect these would be good sellers if they were commercially available here, though they would need frequent updating.  Grade: 3