Jack Wolfskin Men's Jasper Flex Jacket Thunder BlueJack Wolfskin Jasper Flex Mens Jacket Thunder Blue The Jasper flex is a men's waterproof shell jacket, which is highly waterproof, windproof and breathable. The jacket can be converted into a 3 in 1 jacket by buying a fleece wit the short zip system by Jack Wolfskin, or is perfectly fine to be used as shell waterproof jacket by itself. Packed with lots of useful features, a zipped detachable hood, pit zips, 4 x external zipped pockets, 2 x internal