You wouldn’t send your kids out to play in the winter without a coat. Add the Comfort Feature to help protect your animals during shipping. Based on the size of the shipping box, we will add Heat packs and / or Phase 22 Cryo Packs. Heat packs will generate heat for 40 hours. The Phase 22 Cryo Pack will help maintain safe temperature inside the shipping box, absorbing the cold. If the Cryo Pack arrive looking frozen, don’t worry. That means they are doing the job keeping the cold away from the animals. Don’t throw them away, they are reusable.