The batteries that power the electric socks are perhaps the most important component of the idea, considering that they are responsible for delivering the heat to the foot area. As far as watts and mAh, the electric socks on our list are measured in volts,and are usually either 3.7V or 7.1V.
Milliampere hours range from 2200 to 2400, though there may be more variation than that in other models not shown here.