Coronet's most distinctive and well known cameras are their 127 stereo models, which take 4 shots per roll, with two frames being exposed in each shot.
There are three coronet stereo models (as far as I know!), a plain version, the ribbed version as shown here, and the multicoloured version which has random flecks of colour in the bakalite. The plain version has a regular viewfinder, while the later models have binocular view finders - not a particular advantage, as they're rather close together, and difficult to use.
127 format works great for stereo work, as contact prints are a perfect size for viewing. The limitation of four shots per film makes stereo photography an expensive prospect, but the results are interesting.
Watch out for the recoil from the shutters - there are two and they're big, so there's quite a kick when it goes off which can blur the image. Practise without film first. The shutter is cocked by the lever on the front, which requires a good solid pull to prime correctly. As there are no exposure controls use is restricted to sunny (but not too bright) days - approximatly f/11 at 1/50s.