I found one other wooden stacking toy like this one a few years ago, and have had an eye out for another ever since; so beautiful, with its clean lines and unexpected pastel palette and the squared black cap on top. Based on a mark on the other like it I had, I believe that is Russian, which makes sense as it feels rather like a Constructivist sculpture! 1930-40s or so I believe.
6" tall x 2 5/8" in diameter and in very good condition. A few of the stacking rounds are pretty tight getting on and off the threaded post--not a problem, just takes a little effort.