We just bought a pack of these and wanted to pass along the info.
These are Mylar blankets, which are great for retaining body heat. Good idea to have handy if there is an extended power outage and its going to take some time to find somewhere else to go or if you get stranded while riding in a car in winter weather and you don’t know how long it will take to get rescued.
These are in a 10 pack, individually wrapped in zip lock bags. They are $6.95 at amazon and free shipping if you are an amazon prime member. They’ll easily fit into a backpack or in a glove box.
Its one of those things you hope you’ll never need but will be happy to have it if you do need it.