I used the printable foot measure guide from the Crocs website and they fit as expected. sound quality is very good with a great bass response, and comfortable. Keeps your feet dry and very warm even if worn with a regular thickness sock. I love this set up! Great item, works at it should. What a great wireless station! The first day I had to get used to the arch but now I love them. I dont suggest keeping stacks of bricks on them though. 100% recommend this brand, everything is exactly as expected. I went through my entire day at work without once having to stop and save my earbuds from falling out.