Hotronic Power Plus S4 Custom Foot Warmer

With four (4) cells in each Battery Pack, the Power Plus S4 is Hotronic's most powerful, longest lasting Battery Pack! The new Hotronic S Series Footwarmers offer more than ever before. With enhanced reliability and longevity, the new S Series batteries maintain up to 55% of a full charge and 95% of their initial capacity after four years of non- use! Plus, an increase in capacity offers up to a combined 30% in higher average temperatures and longer duration on a single full charge, all when needed most, in the cold