Removable, anatomically shaped cork-latex footbed Upper: oiled nubuck leather Footbed lining: smooth leather Sole: thermoplastic rubber Made in Portugal he Stalon from BIRKENSTOCK is a stylish, robust city boot. Featuring side elastic panels on the shaft, a loop at the back, and a rugged urban sole. The cork PU midsole makes for an instantly recognizable BIRKENSTOCK design. The upper is made from water-repellant oiled nubuck leather.