Polar Tech TP8/MS Ice Brix Viscous Gel Moisture Safe Refrigerant Cold Pack, 4" Length x 6-1/2" Width x 3/4" Thick (Case of 18), White

Very good value for the money. We've got way more than we'll need. These reach freezing temperatures without freezing solid due to being filled with anti-freeze. These also have a soft fiber outside that prevents frost build up, condensation, and frost bite. All this means they are great for use especially with keeping electronics cool in the heat. Also good as a medical ice pack. You could use these in a lunch bag too, but they will be harder to clean than the plastic ones.

I bought these originally for mailing perishables to my dad in Texas. I shipped several pounds of dried beef using the cold packs and foiled bubble pack mailers. The beef and ice packs were still frozen solid 2-3 days later. They work really well if frozen, put in ziplock bags, and used as the top layer in a cooler with ice in the bottom for long distance car trips, too.

My husband needed these to transport medicine on an international flight. After looking around, he decided these would be the best option for his needs--keeping medicine at a refrigerated temperature for 24-36 hours without access to a fridge.He did use some other things to help keep his medicine cool--an insulated bag, insulated pockets that held his medicine, some heavy clothing around the bag to help keep the temperature stable--but everything stayed well within range despite the extreme heat and humidity of his location.The only problem he had is that upon getting to his hotel, he wanted to refreeze the gel pouches to use for his next flight. Three out of four ended up okay, but the last one ended up getting stuck in the hotel's freezer. I'm not sure moisture resistant is the correct term for these pouches as condensation definitely does impact the outer shell.

Great used in a box to ship temperature sensitive items during the hot months.I like that they don’t “sweat”, and are extremely durable.Great for packing in coolers or a lunchbox!I toss a couple in grocery totes to keep the perishables cool while running errands on hot days, or to keep chocolate bars from melting in the car on road trips

I bought these almost a year ago to try and transport ice cream 6-7 hours by car without using dry ice. I've since done a total of 3 of those runs over the last year, all without issue. They are always still frozen at the end of the trip, even when the sun is beating down on the cooler in the car during the summer. I do also make sure to pack any extra air-space in the cooler with newspaper to help keep the temperature longer.I've actually found that I can come back out to the cooler after it has sat in the trunk overnight (so, 24+ hours after they first came out of the freezer) and these will still be partially frozen, and the cooler still nice and cold.tl;dr good for keeping things cold over long distances/long hours.

These packs were a great value. They didn't sweat at all. However, they didn't stay frozen as long as I thought they should.

Stays cold for a lone time. Durable.

These are a great size for can coolers and lunch bags. I really appreciate the lack of condensation as they thaw. That means no mess on the cooler and, when I put them back in the freezer, they don't stick to each other. Replaced all our old random ice packs with these. Highly recommend.