Acropolis Museum - ticket entrance times

[Moxiefurball]

When going straight to the Acropolis museum ticket purchase site, it shows tickets are sold in window blocks of 2 hrs.  For example from 12:00-1400 , 1400-1600  and so on as an example ..  It mentions having to be there at the exact start time for entrance but then you can stay as long as you like. So if I buy the 14:00-16:00 time are they saying I must be there at 14;00 or can arrive anytime within that window? Could I arrive at 15:30 and get in ?

 

[GlennaRoseGoes]

You need to arrive within that window but once inside can stay as long as you like.