The bulloterion, struck with a hammer, was used to make seals, and being of iron, each bulloterion could produce several thousand lead seals. They were normally destroyed when the owner changed office, to avoid fraudulent use, and for this reason very few have survived. As well as one other example in the Zacos collection (to be offered in a future sale), there are five bulloteria known, two in the Bibliothque national, Paris, one in the Sofia Museum, Bulgaria, one in the Fogg Museum of Art, USA, and a fifth in a private collection.