It doesnt matter what style of Birkenstock sandal you buy, Ive found them to all be equally comfortable! Comes down to a few inches above my knees. I got him the 14-15 and he is really happy with the fit. In an ASICS gym shoe I am consistently a 9. or behind me to the left. Its not super grippy to the case, so sometimes opening the case the cover slides but its no biggie. The trip was going to be approx 2500 miles long and last almost two weeks. It came with several extra parts too, which came into handy because i actually broke 2 pieces because i was forcing it into place the wrong way. But the thing I like most about it is the sound quality. 5 and ordering 8 and they fit great so I did the same.