From 1917 to about 1920, shops and manufacturing outlets, issued kapselgeld pieces due to the shortage of small change. They were produced to protect the stamps, which were used instead of money. (The scan shows one of the styles of stamps you will find....'Germania'. The other type just has the value in large numbers and is known as 'ziffer').theIt was seen as a good way for the shop-keepers to advertise their wares/services/produce. For example, several pieces I have were issued by breweries. They followed the American encased postage stamps which were issued in the 19th century. It is a most effective protective device, a small case with a transparent front in which a stamp could be sealed and still be visible. Nowadays these pieces are fairly scarce and thus fairly expensive. Most are about the size of an old English penny (about 30mm in diameter). The backs have the advertisement on them and the front is where the postage stamp is, which can be different values (eg) 5pf, 10pf, 25pf etc. All the pieces are made like a badge, with their edges pushed down to hold the stamp in place. Some of the backs are celluloid and some are metal. There are about 820 different kapselmarken of which about 200 are fairly common, selling between 20 - 50 euros. Unique pieces can fetch in excess of 200 euros!