This provides truly long-term durability. It minimizes abrasion due to pack straps, ski edges, and other stuff that you may shoulder from time to time. Generously sized pockets extend from the lower edge of the PowerShield to the tops of the handwarmer pockets. The considerable storage and ready access that these offer are especially appreciated when wearing a pack. Even around camp it's nice to have them for stuffing odds and ends that you don't want in your hands.
Tapered panels extend below each armhole.
These provide extra ventilation when moving but are pretty much covered by your arms when static. This means that both the front and the back of the collar tilt forward quite a bit. Our collars are patterned in a curve that follows the curve of the neck opening as it goes up over the shoulders and down onto the chest. The result is that the front and back of our collars essentially stand up straight. This avoids having a big gap in the front of the collar where cold air can enter unimpeded.