SIZE 36-40 RUNS SMALL, CONSIDER SIZING UP.

"The legendary two-strap design from BIRKENSTOCK - the Arizona. Modeled on the cork original, this sandal is made from ultra lightweight and highly flexible EVA. These sandals are shock absorbing, waterproof, and skin-friendly. Wear them at the beach, in the garden, or around the gym and after workouts. It's the perfect addition to your classic BIRKENSTOCK sandals." Birkenstock USA

EVA (ethylene vinyl acetate) is a high-quality, very light, elastic material with extremely good cushioning. Great for the beach or any other water activity.