Skogstad's 2.5-layer Brix fabric technology might look & feel like a product made from a single layer fabric, but they've actually managed to tightly press two-layers of material together & a membrane (the 0.5 bit) & the result is a jacket with a hydrostatic waterproof rating of 10, 000mm & super-lightweight for packing down into your rucksack. This is a superb piece of clothing that has been tailored by the weather in the fjords of Norway, ready for a wander with the dog in the cruel April rain in the Midlands.