The Burton ak Insulated Swash pant adds 40g PrimaLoft Silver insulation to a full GORE-TEX 2L shell, built for cold days when a plain shell pant stops being enough. The low-profile insulation holds warmth through the coldest missions without trapping heat once the legs are working, so the added warmth doesn't come with an added sweat problem. What Our Gearhead(R) Experts Are Saying:"I wore these on a bluebird day that never got above single digits, and the PrimaLoft kept my legs warm on the chairlift without cooking me on the hike to the ridge. The GORE-TEX shell never let a drop through even sitting in wet snow to swap boards."