I have not worn thong sandals for many years.  Due to the positive reviews of those tone up sandals, I ordered the black one.  It looks pretty good and as soon as I tried it on... I loved it.  It is so comfortable I was able to walk and go shopping for hours with those.  I usually wear size 5.5 and I ordered size 5 and it fits perfectly.  Plus Amazon has one of the best customer services.  I received my order in about 3-4 days with the free shipping option.