I wear a 12 in regular shoes, but the original 11s I purchased years ago fit perfect. Basically, by providing more room under the laptop, it helps the fan inside your pc (or mac) do its job better by circling cooler air. Works great for keeping my dandruff at bay! they fit like a medium on me and dont really consider my feet wide. If you are looking for the BearPaw/Ugg look but dont want to spend that kind of money then these are perfect for you. 35mm screw on adapter. My memory not being the best, I guess I must have forgotten about the anguish of breaking these bad-boys in. ) Bose/Audio Technica- just the basics. Works perfectly and fits perfectly into my pantry. Just for kicks I tried on some soft bed birkenstocks.