Do they stay warm the full 18 hours (assuming 32 deg F ambient)? If not, how long?
594208
I put them in late at night and have checked in the morning and they are still warm. I would say a good 12 - 14 hrs at least. Usually I have replaced them by then to make it through another night. Use them as warmers for strays in my neighborhood.
1224720
I didn't know, so I put mine in the freezer for 12 hours at minus 17 degrees F. They are still as soft and flexible as at room temperature! Amazing!
973324
This size will stay warm for about 15 minutes when insulated against your skin. Larger packs will stay warmer for longer periods of time.
1914256
Mine seems to keep warm forever. After the whole 24 hours it didn't shut off. Maybe this is defective?? (though I am happy it does not shut off.)
1492957
it all depends what you consider 'warm' ... living in the midwest and dealing with horses etc. etc. ... they hold up well down to about 10 degrees and no wind ... beyond that ... even with a silk liner glove and working ... NO ...
601478
The are one time use, however... I have found that I can wear them in my leather gloves during the morning drive, then wrap my glove tightly with the warmer inside and put it in my pocket... 9 hours later, I still have some heat left for the drive home. The key is limiting the oxygen exposure. I suspect that if I were to put the previously opened packs in a plastic bag while I'm at work, they'd be even warmer for the drive home.
562961
Agree with many other responders -- stays warm for maybe 8 hours -- but definitely not hot after that. Insulation is present, but it's not like a thermos at all.
433012
I haven't had the chance to have them up for 4 hours continuous. I have only had them on for a few minutes at a time since I bought them. Thanks!
252125
They are LEDs so you shouldn't have a problem. I didn't notice them getting all that hot. Granted, I haven't left them on for hours at a time and then tested.
574934
I have never used them to keep something warm. I only use them to carry my water bottle around. Sorry!
1932822
No they don't get hot at all... i had them on for over 5 hrs for a shoot and it was fine.
2017755
Not as long as I would like, but it kind of depends on if you have them just lying on top of your puffy eyes or wedged between your back and the bed which would be warmer. I actually will buy a regular larger gel pack next time because their thickness allows them to stay cold longer, but these are fine for very small areas, and you can rotate them if you're not using them all at the same time.
2124649
They do not stay warm long. Actually they really never get "hot", you get about 15 minutes of warm as long as you are constantly kneading them. After about 30 minutes there's almost no heat at all. Activation is another 30 minutes of boiling water and waiting for them to be "completely" fluid again.
1080885
I suppose they sweat after a certain period of time. I put them in a small cooler of mine that I use like a lunchbox. But I use it as more than a lunchbox, really, because I like to have at least two meals with me at all times -- and they last all day -- i.e., at least 8 hours. But I suppose there are days when I don't get home for maybe 12 hours, and the stuff in my cooler is still cool. By then, the fit and fresh coolers are melted inside, but still cold. And obviously, sweating a bit. I just checked the stuff that I put in there at about 8:30 this morning -- almost 9 hours ago -- still cold. Hope this helps. I suppose they sweat after a certain period of time. I put them in a small cooler of mine that I use like a lunchbox. But I use it as more than a lunchbox, really, because I like to have at least two meals with me at all times -- and they last all day -- i.e., at least 8 hours. But I suppose there are days when I don't get home for maybe 12 hours, and the stuff in my cooler is still cool. By then, the fit and fresh coolers are melted inside, but still cold. And obviously, sweating a bit. I just checked the stuff that I put in there at about 8:30 this morning -- almost 9 hours ago -- still... » Read More I suppose they sweat after a certain period of time. I put them in a small cooler of mine that I use like a lunchbox. But I use it as more than a lunchbox, really, because I like to have at least two meals with me at all times -- and they last all day -- i.e., at least 8 hours. But I suppose there are days when I don't get home for maybe 12 hours, and the stuff in my cooler is still cool. By then, the fit and fresh coolers are melted inside, but still cold. And obviously, sweating a bit. I just checked the stuff that I put in there at about 8:30 this morning -- almost 9 hours ago -- still cold. Hope this helps. « Show Less
1355336
Yeah, nice and warm, Wore them while working the christmas tree lot at Home depot for 2 months about 18 degrees on the regular, also fits under a boggen easy for double warmth.
2196685
45 minutes to an hour. I heat them for 1 minute. I hop into bed with them on and sometimes go to sleep, so I'm not exactly sure of those times. While watching tv I can get about an hour.
98097
Approx. 2 hours , these are ok to ware , but it is not warm enough for me , I'm riding the bike in 30-35 degrees ,