Digitsole Heated Insole
If winter sports give you cold feet — literally — try the Digitsole Heated Insole on for size. These insoles slip into your shoes or boots and activate using their accompanying smartphone app, providing heat in adjustable one degree increments (up to 113 degrees F) to keep your feet comfortable for up to 8 straight hours per charge. A built-in accelerometer lets them double as an activity tracker as well, displaying steps, distance walked, and calories burned in the app. And they make your shoes more comfortable, not less, thanks to a shock heel cushion, flex zone, and arch-supporting design.
Preorder at Amazon – $200