Polyester, Flannel upper 75% recycled polyester (GRS certified), 25% elastic gore 100% Recycled Polyester faux shearling lining EVA midsole 47% Recycled EVA foam, 6% straw & 47% virgin rubber outsole, Happy U tread From the hugely popular Sidewalk Surfer series by Sanuk, the Donna Soft Top Shoreline is a hybrid shoe/sandal combination featuring a shoe upper on a sandal bottom. This patent pending design combines the year-round style and protection of a shoe with the natural comfort of a sandal. Sanuk has added even more comfort! They added an elevated layer of new Soft Top Foam in the midsole for the most cushiony, high-rebound bounce ever and a slightly lifted look. The sandal bottom allows your foot to bend and flex the way nature designed you to walk. And the loose fitting upper allows your foot to spread so it can absorb shock naturally. They are the most comfortable shoes - I mean sandals - we've tried in years.