Birkenstock Lutry Premium Suede Slipper (Narrow) Thoughtfully designed to give you two ways to wear, the Lutry clog is endlessly versatile. A convertible backstrap gives you added security when you need it, and flips up when you want a more relaxed look. It's all grounded in our original contoured footbed for the ultimate support. Contoured cork-latex footbed creates custom support with wear Classic suede upper Suede footbed lining helps keep you comfortable Grippy rubber cork blend sole Convertible backstrap with adjustable metal pin buckle Footbed made in Germany Material Upper material: Suede Suede is a split leather with a napped finish. It has a velvety surface and is very soft to the touch. It also boasts a high moisture absorption capacity. Suede is softer and more flexible by nature and does not have the same stability as smooth leather. The stability of suede also varies from hide to hide. This does not constitute a material or production defect. Insole: Natural leather Natural leather can be recognized by its untreated surface. BIRKENSTOCK purposely does not treat surface grains and other characteristic features. BIRKENSTOCK uses sturdy leather with a thickness of 2.8 to 3.2 millimeters as upper material. Footbed material: Cork Cork is a sustainable material extracted from the bark layer of the cork oak. This natural product is insulating and offers very good cushioning. Outsole: Rubber Because of its high elasticity rubber is very well suited for outsoles. Thanks to this property it supports the natural rolling motion of the foot. Rubber is also very robust and has good cushioning.