In ATF nylon, specially for use at sea, these trousers are absolutely waterproof and allow exceptional freedom of movement. They are reinforced at the knee and seat and have a double Velcro and zip closure at the bottom. Features:Advanced Technology Fabric. This brand name is used for a range of diferent fabrics that share the same characteristics, they are all waterproof, breathable and thermoregulation.Waterproofing Resistance to water is expressed in millimetres, which represent the height of the column of water wich the fabric is able to whitstand during laboratory tests before allowing liquid to penetrate.Breathability Two enviroments are artificially created with different hygrometic conditions and vapour is forced through the fabric, after wich vapour penetration is measured, with the result expressed in grams of water vapour per sq meters of fabric in 24 hours.Thermo-Taped Seams The heat application of a special backing tape on fabrics offers total protection against water penetration along seams.