The Phantom is surprisingly lightweight. Despite this, its Pertex Shield 2.5-layer fabric provides protection from both rain and wind, while maintaining high breathability. The water column and breathability ratings are both 20,000. The Phantom is easy to pack and take along whenever theres a chance of weather changes during a run, day hike, or race. Its pack size is extremely compact. Due to its 2.5-layer construction and ultralight fabric, this jacket is not recommended for carrying a backpack or heavy load. Rab has designed it specifically for training runs and trail or mountain running events. - Slim fit - Rear hood panel vent allows incoming wind to escape - Hood can be rolled down into the collar when not in use - Partially elastic hem for a secure fit - Ergonomically shaped sleeves designed for running posture, keeping arms in a slightly bent position - Center back length This product does not contain PFAS compounds.