Birkenstock Womens Boston Shearling Clog Steel Blue Size 40 N Suede Soft premium suede upper with a matching adjustable strap for a perfect fit. Anatomically correct cork footbed crafted from cork that is 100% renewable and sustainable encourages foot health. The shearling lined contoured footbed will mold to the shape of your foot creating a custom footbed that supports and cradles you each and every step. Raised toe bar is designed to encourage the natural gripping motion of your feet exercising your legs and aiding circulation. Neutral heel profile and deep heel cup keeps the natural padding of your foot where it belongs under the heel distributing your body weight more evenly.