UniHeat Heat Pack 40hr.
- In stock, ready to ship
40 hour UniHeat heat packs (shipping warmers) activate in approximately 40-50 minutes. They are slightly cooler than the 30 hour heat packs, and reach their peak temperature in approximately 15-18 hours. The 40 hour shipping warmers are the most popular for those who are shipping reptiles, amphibians and insects. Not recommended for 2nd day shipping.