On Thu, 12 May 2005 20:05:33 -0400, Sal D'Ambra
wrote:
345 is a Calculator - circular slide ruler in a watch style case. Russian?

My Dad still has several of these.

They're labeled from a maker of aviation charts, so it probably saw
application with manual navigation methods.

One is attached to strap-on knee boards. I don't recall what was on the
other knee.