You may have learned not to expect too much from “space blankets” and other ultralight emergency blankets. Sure, Mylar blankets reflect heat but there is the issue of conductive heat loss. Without an insulator, heat will actually be lost. Some have explained it as feeling hot and cold at the same time. The Heat Saver uses an innovative design to help with these pesky issues.

• The dual-layers help retain heat and reduce the chance of conductive heat loss. Air is one of the best insulators out there, and this design takes advantage of that fact. The dual layers actually trap a cushion of air between the layers that can Velcro shut. 
• One layer is dark green to help absorb heat from outside sources like the sun.
• The inner layer uses the same material as common reflective mylar blankets, so it has the same benefits of reflecting and retaining high amounts of body heat, but without the conductive heat loss disadvantage.
• This wind and waterproof blanket is reusable as it was created with a Velcro design so you can easily seal the air in, or unseal it to let the air escape so it can be conveniently stored.