RAB says about the Prosar Shorts

Why stop when the temperature drops? Stay comfy on cold winter climbs and ski tours with the Prosar Short, the ideal lightweight down short for extra warmth and protection.The Prosar Short is built from Atmos™ 10D fabric with 800FP down for a weight of just 266g. Packable and lightweight for the easiest possible carry when climbing a rock face or skinning uphill. The ergonomically shaped hem and fully adjustable waistband ensure a comfortable fit. Full-length YKK® side zips enable you to pull them on over ski tour pants or bulky boots when you reach the summit.They have resilient Stratus™ synthetic insulation in the seat for added durability. Comfortable, practical, easy to carry and quick to put on, the ultralight Prosar Short delivers protection against wind and cold without the slightest restriction to movement.