Just learned about the free sprung special balance 730 Elgin. Well described in trusted-forwarder.org/elgin/history/fm/730A.jpg. $350. got a good gold one. seller's photos. Thought others like me would not know about this technical improvement just before U.S. Elgin died. The web site may be best reached by googling 730a Elgin. It is a good one showing a couple Ranfft informative photos. I now have 1868 and 1958 Elgin best gold cased examples. Both actually fairly common but to me interesting.