Polyurethane is an industrially produced plastic in which millions of small air bubbles are created by foaming under high pressure. This makes the material particularly light and at the same time provides good insulation. Polyurethane, also called PU, is mostly used in work boots, where resistance and comfort are important. Pu boots maintain their elasticity even in cold conditions. Compared to a PVC boot, the PU rubber boot is approx. 35% lighter.