Ok, I liked the first version so much that I decided to make it better. As unfortunately being made out of heavy paper, it was not very durable. Thus it is not very practical. This new version works the same as the old one but it is made of plastic and slightly smaller. This will easily fit in a jacket pocket.
Here in Germany you can buy this craft plastic at most hardware stores for a few € for a good sized piece. The aluminum tape came from a €uro Store, the European equivalent of the dollars stores of America.