My boyfriend got some from his work a while ago, because he thought they would be good in pockets to keep hands warm. I have found that they dont really stay warm for very long. I was considering using them if i got some fish while we we up in Rotorua/Tauranga, that way i could get a new one going when the first got cold. But i dont think they would be that great when shipping fish. I think a really important thing that some people forget to do is to write on the box that it needs to be morning delivery as i have had some arrive at 2 and 4.45 and they were pretty cold.