With a waterproof rating of 5,000mm, these trousers are designed for hunting ducks, geese, teals, spoonbills and other waterfowl. 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. A component with a waterproofing resistance of 5,000 mm can withstand the pressure of 5,000 mm of water (which corresponds to approximately 3 hours of heavy rain).