From: The Gemmary
We have posted the following Curta I on ebay: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=7986844
Curta Type I Mechanical Calculator, serial number 18539, with rounded handle top, no arrow on the handle top and no red ring under the handle (all early Curta I features). The calculator is in very fine overall condition showing virtually no wear; it is also fully functional and works very smoothly.
The original metal carrying case is an example of the earliest and rarest type of Curta carrying case. It has right-hand threads (it opens counterclockwise); normal Curta carrying cases, both metal and plastic, have left-hand threads (they open clockwise). It also has no arrow under the Curta name indicating opening direction. The case is in very good overall condition, showing minimal wear. Out of the over 50 Curta calculators we have sold in the last 5 years, we have only handled one other Curta I with such a case. In fact, we only know of two others in the private collection of a very advanced calculator collector. This is an opportunity to acquire one of the most interesting and important Curta rarities for your collection.
R.C. Blankenhorn The Gemmary
The X-Number World of Calculators