Select Burton Imprint Liners now come pre-wired and ready for heat! Feet frozen? Crank your Burton/Therm-ic Heatpacks to a toasty 104 degrees. Shredding all day? The heatpacks have enough juice to last up to 14 hours on a single charge. Includes 2 Heat Packs, batteries, charger and cords.
I bought a TON of these last year and I would say that one out of every 5 didn't charge nor hold a charge. I also agree with the other Review, light flashes or stays solid to soon while charging... so Unsure if they are getting a 100% Charge
The battery packs are supposed to be fully charged when the lights blink; however, I'm not sure how accurate the lights are...we were up in Maine and the things died before lunch (single digit temps). On our last trip (warmer day), my girlfriend turned the heaters on mid-day and they lasted 'til the end of day. I picked them up cheap, and she gets cold fast, so I figured it was worth a shot. Still trying to decide if they're worth it...when they're on, they do keep her warm..