I've got the adverts and descriptions for the whole range in a British Journal Photographic Almanac, but the book's in Turkey at the moment.
The 50mm lens indicate it's not a 120 camera, it may be a 127 version from the early 1930's. Don't pay to much for it as very little film is available.
Certo Dolly Is a vest pocket sized , of around 1934 uses 127 film for 8 exposures of 4X6.5 cm and has a Tessar f3.5 lens in a Compur shutter with an average auction price of £60 ($ 87 US)