Sliders by Birkenstock The Madrid mule slider by Birkenstock is a design classic and features a contoured cork footbed, a single strap and a buckle fastening.  - Mocha birko upper - Suede lining - Cork and natural latex sole - Narrow fit About Birkenstock “The mastery of shoe making and the devotion to bring style and comfort to the people have persisted from one generation to the next” Over many generations, the Birkenstock company has gathered extensive knowledge in the area of foot health. This knowledge and experience is the foundation of their proven, high quality Birkenstock sandals and shoes.