Model: (Bewi) Amateur
Price (new): $14.95
Cell type: Selenium
Measure type: Reflecting / Averaging
Bertram, as did a lot of companies, liked to take the same basic item and sell variations of it to fit different price ranges and tastes. This guy is virtually the same as the Chrolon / Chronos / Chrostar, all of which were being made around the same time. This was the low-end of the line; it lacks the nifty pop-up hood that protects the face which all the others had, and it lacks the swing-out doors of the Chronos. But it's still nicely styled and it's the earliest meter I've seen that was available in several different colors. The "Bertram" branded meters have either a black or white casing with a black face; the "Bewi" branded meters have a white case and a red face. I think the red/white combination is the best, but I only have this early "Bertram" edition.
This is very small—for some reason in photographs I pictured it as being about the size of a pack of cigarettes, but is about 1/3rd as large. The dial and face are very, very close to the Chrolon/Chronos/Chrostar, and I suspect there's a lot of commonality in the parts between them all. The big difference is that this one is shaped like a lyre instead of a watch, and it has no protective cover for the meter face. It does, however, have a protective flip-down gate on the end to protect the meter cell.