Remember when I made the foil credit card holders. I have just heard that thieves all over the world have a new scheme. They work in pairs with a device. They watch your car, and when you walk away, one follows. The device nearest you signals the device near your car and they gain access to your car and possible it's ignition. I would like to make a cover or large block keychain to cover the chip in the key. The article said to cover your keys in aluminum foil. I wonder if that metallic hot/cold stuff would do better than a thick mylar. I never did find a device to test my credit card carrier. I guess only the thieves have them. Lol!