- HERMES cute Mule half-slip Birkenstocks are really in need of versatile slippers in summer. They look good no matter how you match them. They have a casual and high-end feel and are also very comfortable. They are paired with a variety of colorful socks and are popular with imported cow suede. Fabric sheepskin lining Tpu non-slip and wear-resistant outsole Size: 35-41,