Men's Birkenstock Boston Natural Leather Clog Shoes - Brown - Slippers A versatile classic, the Boston clog from Birkenstock is a staple all year round. Constructed with a natural leather upper, anatomically formed natural cork footbed with a leather lining and EVA sole offering complete foot comfort and optimum arch support. Fitted with an adjustable metal pin buckle fastening and finished with signature Birkenstock branding. Natural Leather Upper / Suede Lining / Anatomically Formed Natural Cork Footbed / EVA Sole / Adjustable Pin Buckle / Birkenstock Branding.