The Boston clog from BIRKENSTOCK features a soft, high-quality wool felt upper. It includes an integrated strap and a metal buckle for individual adjustment to each foot. The clog has an anatomical cork and latex footbed, with a suede leather oversole and an EVA sole. Key details include an individually adjustable metal buckle and "Made in Germany" origin. The hypoallergenic, flexible leather insole gently conforms to the foot, adapting to its contours with an open-pore surface that is thermoactive, maintaining a pleasant foot temperature. The footbed is made of cork, a renewable raw material from cork oak bark, providing thermal insulation and excellent shock absorption. The outsole is made of EVA (ethylene vinyl acetate), a high-quality plastic offering excellent shock absorption, lightness, and elasticity.