Women's Birkenstock Madrid EVA Big Buckle Footbed Sandals This is a new and modern interpretation of the BIRKENSTOCK classic Madrid. This version features our popular Big Buckle made from a stainless synthetic material and makes an impression with its durability and minimalist design. Modeled on the cork sandal, it is made from the ultra-lightweight and highly flexible synthetic material EVA. The high-quality, odor-neutral EVA has been tested for harmful substances and combines numerous positive attributes: it is very light, highly elastic, shock-absorbent, water-resistant, and skin-friendly.