The Meisterstück No. 25 was, according to the Rösler book, made from 1935 to 1947 and belonged at the time to the standard programme; measured by today's standard models like the 146 it is significantly rarer, but turns up on eBay regularly. Three mechanism variants exist: safety, push filler and lever filler; the functions are documented e.g. on penexchange.de. The green colour arises through oxidation of the hard rubber and can be partly approximated again with a light polish (e.g. Wenol, which Montblanc also uses); however, every polish removes material. An official, complete model archive of Montblanc does not exist, since the factory archive burned in the Second World War; with a defective ink-sac seal, a professional repair is worthwhile, e.g. at maxpens.de.