Birkenstock Madrid Essentials Eva White Slide Sandals Size 37 Like New! The Madrid EVA lets you take the iconic style you love wherever water is found. Made completely from ultra-lightweight EVA, this style is water-friendly and flexible. Experience the benefits of our anatomically shaped footbed, whether you're headed to the gym or the pool. Anatomically shaped BIRKENSTOCK footbed Made from a single piece of molded EVA Water-friendly and ultra-lightweight Ships within 1 business day!