Apparently the CROCS with linings are the same shells without the linings so you must order ONE SIZE LARGER than you really need.  I learned this the hard way.  These do not have the back strap, so don't expect them to stay on as well as the ones with the strap.  Again, learning the hard way, I would have ordered one with a strap so my daughter can wear them them to school and play on the playground easily.