Heat Factory® Heat Packs fight the shivers!
Don't suffer in the cold... just open one of these and get toasty! They're all compact and safe. Activated when opened. Just use them for hours and then toss them out. Designed to provide safe heat in restricted air space of shoe or boot. Each 2 1/4 x 3 1/2". Provide 6+ hours heat.
Enjoy the outdoors without the shivers!