Sitka Women's Fahrenheit Jacket. Highly specialized for waterfowl pursuits, the Fahrenheit Jacket is a windproof insulating midlayer featuring GORE-TEX INFINIUM with WINDSTOPPER Technology. Mapped for moisture management with PrimaLoft down blend from elbow to elbow and fully synthetic PrimaLoft through the forearms, the Farenheit provides ample warmth and a free range of motion for raising and swinging a shotgun.