For active pursuits in colder weather, Rab has designed what can be best described as an ultralight cross between a wind shirt and a soft-shell jacket. The body fabric is an 86% polyester, 14% spandex blend (called Matrix SWS), and the shoulders/sleeves are constructed out of a tougher 90% nylon / 10% spandex blend (called Matrix DWS). All of that spandex means it has a nice stretch which in turn also means that it is cut quite slim (for reference the photo is of me in a size L, I typically wear a size S or M in other Rab garments). The long cut sleeves have thumb loops and the close fitting hood is designed to fit under a helmet. The inside of the fabric is smooth (i.e. not brushed). The estimated weight for this jacket when it hits production is 12 oz.