Design: Upper, lining, and sole all made with one piece of EVA Waterproof, washable, and ultra lightweight In-Shoe Comfort: Anatomically shaped BIRKENSTOCK(R) footbed made with EVA Deep heel cup supports the foot tissue and holds the heel bone firmly in its natural position Heel mould activates the calf muscles, stabilizes the back of the foot, and improves gait and coordination Added support for the interior and exterior arch Transverse arch support runs through the middle of the footbed and stabilizes the metatarsal bone for a solid stance Raised indentations at the front of the footbed ensure that the toes remain loose and spread out in their natural position Drawn up footbed protects the toes during the rolling motion of the foot Durability & Traction: EVA outsole cushions every step and smooths out irregularities in the floor