What are Uniheat heat pack?

Uniheat is a brand name of heat packs. Heat packs are used to keep
items warm during shipping. There are different grades that will last
different lengths of time. They are used to keep fish, small animals,
plants and crickets warm when shipping fall, winter or spring. They are
a cheap one-time used item utilized for shipping. They can be used for other
purposes but shipping is the primary one.

They contain sawdust, iron fillings, salt and water. They are environmental
friendly. They do not contain dangerous chemicals. You remove the
plastic seal and they start oxidizing the iron to generate heat. They
are different durations 24-hour, 48-hour, 60-hour and 72-hour. You pick
that one that will last the right amount for the trip. They are fairly
heavy about half a pound. I use them to ship fish in the winter. They
are great for shipping plant. You should place them in the package so
they are not touching the items that you are shipping. They can heat up
to over hundred degrees so you don't want them touching the plants or
fish bags.

When you remove the heat packs plastic cover, there is a side with red marks. This is the
side that the oxygen is absorbed and should be
exposed for best results. This pack works best in warmer temperatures.
If the box get below freezing the packs cease functioning. It might not
work in sub freezing temperatures.

They weight about half a pound each. The 40 hour are lighter about three ounces each. Remember to figure that in your
shipping weights for your package. You do not want the heat pack in
direct contact with the plant or bag of fish. I usually use newspaper
to create a wall between the heat and living items being shipped. You also do
not want to use too small of a box either. I suggest keeping at least three
inches clear around the heat pack.A customer was telling me how to tell if a heat pack has been sitting too long. If it has because rock hard, it has died. Sometimes over the summer they can go bad. It best to use them all during a one year period. I had some heat packs kept over the summer that worked fine during the fall. Try to buy them in the amounts that you will use.