Originally made with rubber and a lace-up leather upper, Lacrosse kept the classic look but swapped the rubber for an AeroForm shell made with polyurethane. This provides more flexibility and will keep feet warmer because the polyurethane won’t transfer cold to your feet like rubber can. The inside is smooth and seamless, adding to the overall comfortable fit and feel. Aeroform shell bottom Seamless interior Suede upper Timber top outside Waterproof lining Men's Lacrosse Aero Timber Top Slip-On Boot - Clay Brown