Best-selling clog in an ultra-lightweight style. The Boston EVA is made from water-friendly material, giving you a flexible design built on the contoured footbed you love most. The perfect pair for pre-workout, post-practice and all the rest days in between. Contoured footbed for legendary BIRKENSTOCK support Style made from single piece of EVA Water-friendly, flexible & lightweight Adjustable strap with tonal pin buckle Made in Germany EVA (ethylene vinyl acetate) is a high-quality, very light, elastic material with very good cushioning. As a result, it smooths out slight irregularities in the floor and ensures that every step is softly cushioned.