Serene I Barefoot Mules - Size EU 39 (US 8) The Serene I combines comfort and style with a plush inner lining for warmth and softness. Its backless design offers easy slip-on convenience, while the minimalist look is perfect for everyday wear or lounging. Zero-Drop Design: Promotes natural flexibility and comfort. Wide Toe Box: Provides extra room for toe movement, reducing pressure and ensuring a comfortable fit. Backless: Enhances flexibility and convenience. From a smoke-free home.