The Helly Hansen Alpha Lifaloft pants pair a Helly Tech Professional waterproof and breathable shell with Lifaloft insulation, so the warmth comes without the stiffness of a heavier liner. Four-way stretch fabric moves through a full range of motion, and thigh vent zippers let heat out fast when the pace picks up. A Recco transponder adds a layer of findability for backcountry days. What Our Gearhead(R) Experts Are Saying:"I've skinned up in these on a bluebird afternoon and never had to strip a layer. The thigh vents dump heat the second my legs start working, and they seal right back up for the ride down."