I've been looking for one of these for a while and this one popped up on ebay. Pretty rare to find, especially in good condition.
Interesting fact - it uses a standard close-up lens element for the monocular. It's the size that would be fitted into a 58mm filter holder. So easy to replace or change to fit your eyesight. The one fitted was a +4 dioptre. However, by experiment, I found I needed a +7. No such beast exists so I glued a filter rim inside the hood so extra filters could be added to make up +7. Perfect.
Interesting fact - it uses a standard close-up lens element for the monocular. It's the size that would be fitted into a 58mm filter holder. So easy to replace or change to fit your eyesight. The one fitted was a +4 dioptre. However, by experiment, I found I needed a +7. No such beast exists so I glued a filter rim inside the hood so extra filters could be added to make up +7. Perfect.