With their 2000 mm waterproofing rating, the waterproof driven-shooting trousers 520 provide excellent protection from the rain. We measure a fabric's resistance to a water column, in mm (based on the ISO 811 standard). The higher the pressure, the more waterproof the tissue is. Components scoring 2000 mm can resist the pressure from 2000 mm of water (which is equivalent to a rain shower lasting 2h).