OLUKAI Women's Ho'Opio Leather Sandal Synthetic Imported Synthetic sole Platform measures approximately 0.25 Outsole: Non-marking rubber outsole designed with a flowing seaweed pattern for both traction and durability. Footbed: Anatomically molded micro-textured PU midsole with laser-etched hook logo. Outboard Strap: Built into the outside surface of the sidewall instead of the footbed, our unique Outboard Strap Construction offers a free yet secure fit for the most comfortable arch support possible. Non-marking Rubber: Our thermoset rubber is a compound of natural and synthetic rubber that will not leave marks or scuffs on surfaces of any type. Our gum rubber outsoles, as a natural material, will always naturally be non-marking.