Another vote for frozen water bottles. The best that I have found are 1L sterile water bottles that are used in medical facilities. They are rectangular and nest well together in a cooler.
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Another vote for frozen water bottles. The best that I have found are 1L sterile water bottles that are used in medical facilities. They are rectangular and nest well together in a cooler.
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If you have room in your cooler, I like to use my 10 liter MSR Dromedary bags (https://www.msrgear.com/water-treatm...dary-bags.html) and freeze drinkable water in those. That way, you'll have a giant ice block that'll keep, and can be frozen again and again, and a decent sized emergency supply of drinking water if you need.
Also good if you have multiple, as you can throw one into your cooler to pre-chill it, and then swap them out once you have to use the cooler.
Cooler Shocks are best I've found so far, we've been using them since at least 2015.
Wore out one of the big foil ones 10x14 inch we bought in 2015 year or so ago with lot of use it finally developed a small leak ~2021 so at least 6 years of use.
We replaced the large foil versions with their newer big solid plastic ones 10x13 inch.
We have several of the smaller foil ones 6.5x7.5 inch that get even more frequent use, bought 5+ years ago, used pretty much every weekday and some weekends, and no problems other than sharpish corners when they are frozen solid can nick your finger or ziplock bag if your not careful.
Except for our lunchbox sized coolers we use various Colman Xtreme coolers with Cooler Shock "ice", gf uses one of the smaller xtrem coolers for her craft shows and it will keep stuff icy cold for more than a day even when its 90 degress like today and the cooler is stuck inside the car for first half of the day while she is working her day job before heading to craft show.