Inside, we've upgraded our low-profile and fully rechargeable heating system using the premise of countercurrent exchange-the transfer of heat through orienting the heat source perpendicular to the blood flow in the wrist. The heating element now wraps around the inside of the wrist, which increases the mitt's warmth and your body's ability to warm itself. This system includes three-levels of heat that are controllable via an integrated LED switch. On the exterior of the mitts, a premium goat leather shell backed up by a fully waterproof and breathable GORE-TEX insert stands up to the rigors of long days on the mountain in variable conditions. We've also increased the PrimaLoft® Gold insulation on the back of the hand and added PrimaLoft® Gold to the palm with Grip Control for better control while skiing. A zippered carrying case and included outlet adapters make for easy storage and charging while traveling.