Havaianas Women's Fit Thong Sandal,Grey/Silver,39/40 BR (9-10 M US) 100% Synthetic Synthetic sole Brazil size 35/36 fits US Women's size 5/6, Brazil size 37/38 fits US Women's size 7/8, Brazil size 39/40 fits US Women's 9/10, Brazil size 41/42 fits US Women's 11/12. US size stamp on shoe is based on Men's shoe size