Description Not for serious trekking but for when you just need a waterproof layer to throw on on your way home from work, walking the dog or on a breezy stroll along the beach, Mac in a Sac is the perfect choice. As well as packing down small enough to fit in your day pack or handbag, these jackets are fully waterproof (7000mm) and breathable (7000g/m2) with a foldaway hood and water resistant front zipper. Hand warmer pockets, a rear vent and elasticated cuffs complete the jacket.