Upper material: leather. Inner material: leather. Sole: thermoplastic rubber. Closure: buckle. Heel shape: flat. Not waterproof. Available sizes: 3.5, 6, 7.5. Gioseppo Sandals NIOAQUE Available in women's sizes. by Gioseppo. There's nothing better for a hot summer day than a pair of sandals from Gioseppo. This design has a leather upper and synthetic sole. With their leather lining and leather insole, these shoes are very comfortable! The sun will shine again!