The upper takes inspiration from the studded upper of the 15-50 cross-country model. It borrows its construction from the first two GEL-SONOMA trail shoes for maximum comfort in everyday life. Product details • Sports shoe • Flat heel • Fastening: lace-up. Uppers: 100% polyurethane. Lining: 100% polyester. Cushioning: 100% polyester. Sole: 100% rubber.