5 or a 38 and when I received those, they were way small for my feet. I have a pair for sale. 5 in most shoes, but this 8. Ive owned them for about 8 months now and the fabric is holding up on the most part (I tried to remove them a little too forcefully once and a thread popped out). It came quickly but was sent in one of those padded envelopes. I would highly recommend that you get this mic if you?re looking into starting a podcast or want to records some music! Mic sounds great and clarity is strong. Of course! Extremely comfortable shoe! This flip flop runs SMALL.