Birkenstock Birki's Blue Slides Sandals Shoes are a comfortable and stylish Great choice for women. Barely worn. These sandals feature two straps with buckle accents, a solid pattern, and a flat heel style. They are made of faux leather and are available in EU size 40 and US women's size 9. The Birkenstock Birki product line is known for its quality and comfort, making these sandals a great addition to any wardrobe.