Phase/cryo packs for shipping

Hey everyone!

Sending out some snakes today and I had a chat with redline just to make sure I was following within the parameters to remain covered by their insurance. One of the individuals I spoke with asked if I had a cryo pack or phase pack that I could use for the shipment.

I’ve heard a little about these, but not much. Anyone here have much experience using them? We ended up deciding that based on where I was shipping to, I didn’t need any heat pack, but was told that a phase/cryo pack would hav been the most ideal in my scenario.

Just wanted to see any feedback others had, or experience with them.


Phase 22 packs act as a sort of temp buffer system. you gently heat them to liquid phase when you expect there to be cold temps or you leave them as a solid if you expect there to be hotter temps. The energy it takes to “shift” the material between liquid/solid prevents extreme swings inside the box. I have heard of some people using them in conjunction with heatpacks during winter to make sure the inside of the box does not overheat as well

I have used them a few times during warmer months and around this time of year when temps seem to be all over the place


Thanks for the in-depth explanation. I know they can be a little pricy. At least the ones I looked at were about $5 a piece. So just didn’t know if it was worth having some on hand. I’m still getting my head wrapped around shipping. These 2 snakes are only my second shipment I’ve ever done. So I don’t have experience with cold packs or anything. My first shipment did need a heat pack but that worked out okay.


The biggest thing to remember when shipping is that heat is a much greater danger than cold. An overheated animal can die in a very short time whereas an animal that is cold can be fine for days. Speaking from experience, I had a package get delayed/lost for four days in December during a rather nasty storm. No heatpack and the snake was fine when he finally arrived