Slider sandals by Birkenstock The Madrid single strap sandal in white comes with an adjustable strap and boasts a synthetic Birko Flor® upper set upon a rubber sole for maximum grip. The padded footbed gives an orthopaedic fit that\'s comfortable for walking.  - White synthetic upper - Cork and natural latex sole - Regular 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.