Did you loose a battery? Do you want extra longevity for your heat by having back up batteries? Did a battery get old and won't hold a charge? Then ordering a
Hotronic S4 Power Plus Battery Pack
replacement or spare battery for your ski boot heaters will help. Keep in mind the Power Plus S4 batteries can only be recharged using the Hotronic Power Plus m4/m3, e4/e3, and S4/S3 battery charger with the white plugs.
HOTRONIC S4 BATTERY INFORMATION
Weighs only 5 ounces per battery pack and powered by high capacity, cold temperature operation, with 4 (four) NiMH cells.
Each battery has four (4) temperature settings for your personal comfort. Settings are easy to adjust by push button controls on top of the battery packs. Easy to read battery pack LEDs indicate setting selected and power on / off.