Premium Materials Every pair of Birkenstocks is made from the highest quality materials. EVA Upper / EVA EVA - Ethyl Vinyl Acetate is a non-toxic synthetic compound. Creates lightweight and flexible footwear that is shock absorbent. Also resistant to water, oil, and grease. It can shrink at high temperatures. Made from Ethylene-vinyl acetate, this footbed is lightweight and flexible and still offers contours and arch support while being completely waterproof. The Barbados The BIRKENSTOCK Barbados is a waterproof lightweight, sporty slide design with a hexagon pattern and logo lettering. Modelled on the cork sandal, this sandal is made from one piece of light, flexible and waterproof moulded EVA. A waterproof alternative to Classic Birkenstock sandals. Great for the beach or beside the pool. This style must not be left in direct sunlight and are not designed to be worn day in, day out, for long periods of time or on lengthy walks. This EVA style is manufactured in the REGULAR width only. This product is vegan.