Even experienced professional sellers occasionally offer counterfeits, e.g. from a normal 136 and celluloid assembled supposed rarities that can achieve high prices in the high four-digit range. Especially with old writing instruments, counterfeits are often so well made that even collectors do not recognise them at first glance. If a seller is pointed to a counterfeit and does not react or only refers to the previous owner, this behaviour is to be classified as bordering on fraud and damages his credibility. Buyers should exercise particular caution with such providers and have offers in case of doubt checked by experienced collectors.