My son has been doing a lot of camping and hiking with the Boy Scouts. He has been complaining of cold hands. I saw a great deal on this power bank with a handwarmer function. I purchased it and tried it out. It has two settings for heat - low and high. My son used it this past weekend and loved it! I think it would have to be used on low if he wanted it to last for a whole camping weekend, but on high for a day hike it is perfect!