Counterfeits of old Montblanc pens, e.g. of the 1930s and 1940s, are rarer than with current models but, through high closing prices, particularly dangerous. Platforms like eBay cannot recognise such offers independently and can only intervene if the rights holder reports them as a plagiarism. Certain counterfeit types, e.g. those with Krupp nibs, turn up repeatedly in identical construction and are documented in specialised articles and forums.