I have a grande total of two, now I've found very little information on the brand, as has many before me, but Mikrolisk states that the company was formed by E. Petremand in Colgny (part of Geneva), Switzerland on April 12, 1952. All of the examples I've seen have the noteworthy Felsa Bidynator (very first bi-directional auto) movement inside. Here's my tiny collection , a ref. 602 (Moonphase) and a ref. 502: ... interestingly, here's an auction from a few years ago that was selling a Trematic TDMP (ref.602) like mine, but it had the 'Tiffany & Co.' name on the dial: I know there's a small number of Trematics among our members, so please do share yours, and any information you may have on this seemingly 'phantom' Swiss brand!