These cooler packs can be a bit fiddly to fill up with water; I used my own funnel. But they work well. As these freeze at 18F (-7C) I would not use them for keeping food cool, it is likely to freeze them. But they are great at keeping food frozen, when defrosting a freezer. I have used then to keep food below -10C for over 12 hours.

Come on Party outdoors

I have used cooler shock blocks for years... and this plastic format has various advantages over the cooler shock's mylar version of the same product. This blue plastic version is much gentler on your hands when handling the cold cooler pack.My complaint is how difficult it is to mix the water into the packs during set up, without causing a powdery non functional area of the cooler pack. Even after creating six of these packs I still didn't master the process. Essentially, you want to add water slowly and mix it up as you go... Keep the powder away from the handles... this is the number one most difficult spot to get the water into... almost all of my cooler packs have a dry powder section in the handles where I couldn't get the water to reach.Add a bit of water... then shake it up... add some water... shake it up... move the powder around... add some water... shake it up... until the pack is full. Finally squeeze it and hold it upright so all the air comes out the top... then quickly put the top on. Grab a friend for the last step so that you can squeeze the pack tight, while the friend screws on the top.Honestly, it might be better if the pack wasn't clear... because if I couldn't see that the pack wasn't mixed correctly, I wouldn't notice any difference and then it wouldn't bother me... Ignorance is bliss.

As far as temperature goes, they do the trick, however 1 of the 3 started leaking from the lid, and I checked thoroughly that it was screwed on properly so it was not that. Otherwise it works well enough, can't say I'd get another since the one pack will slowly leak out.

Does not stay very cold for longer than 12 hours individually. If you put two together, you’ll get 24 hours of cold, however. But not this 48 hours that they are advertising. Not ever.