When temperatures drop past your toes' liking, use the Therm ic SmartPack ic 950 battery pack to power the ThermicSoles in your ski or snowboard boots and keep on skiing or riding with toasty toes. These packs clip to the tongues of your ski boots and power the insoles for up to eighteen hours on the lowest heat setting. Three heat levels accommodate frigid nights in winter as well as warmer days in the spring, and its Impulse Control system helps stimulate your blood circulation to keep your feet energized. This pack also includes a global charger that powers the Smartpacks' lightweight lithium ion batteries quickly no matter what country you're in. Some ski boots by Atomic, Burton, Dalbello, Head, and Salomon have ThermicSoles in them already. Some have ThermicInside compatibility. Some have neither. If your boots already have ThermicSoles in them, all you need is this pack. If your boots don't have the soles, you need to grab a pair of ThermicSoles to go with this pack. ThermicInside compatibility will make it a bit easier to set up the system, but if your boots don't have that either, with a bit of craftsmanship, a pair of scissors, and some duct tape, you'll be set to integrate the system with your boots.