The BIRKENSTOCK Boston is a true classic that can be worn all year round. With its refined, individually adjustable design, Boston has long since achieved legendary status. The particularly thick, oiled nubuck leather upper has a raw edge design. Anatomical cork and latex footbed. Upper: oiled nubuck leather. Oversole: suede leather. Sole: EVA. Details: a strap with an individually adjustable metal buckle. Made in Germany. Upper: Greased leather. The greased leather is recognizable by its untreated surface. BIRKENSTOCK chooses not to treat the ribs and other characteristic features. For the upper, BIRKENSTOCK uses a leather of 2.8 to 3.2 millimeters. Insole: Insole. The hypoallergenic and flexible leather insole gently hugs the foot and adapts to its contours. The open-pore surface is particularly thermoactive and keeps the feet at a comfortable temperature even during intense physical activity. Footbed Material: Cork. Cork is a renewable raw material that is extracted from the bark of the cork oak tree.