These knee high boots by ASOS Collection have been made with a leather upper. The details include: a knee-high design with a side zip fastening, a leather zip pull, a round toe, a stacked heel and a slim sole with a textured trim. Upper: 100% Real Leather. Lining sock: 50% Polyurethane, 50% Textile. Sole: 100% Resin. Heel: 11cm.