The Leonardo Sketch Pen in sterling silver is a very rare variant so far hardly documented; even experienced collectors had previously not laid eyes on such a piece. It is presumably a special production, in one concretely reported case from the loft sale of a designer (R. Wilson), which was auctioned via a US auction house. The hammer price of around 400 US dollars lay significantly below what comparable pieces usually achieve, which additionally underscores the rarity of this offer. Reliable information on edition size or on the official distribution channel does not exist.