Here's another one of my favorite slide rules-- a Post Versalog, model no. 1460. It has 23 scales-- probably my favorites are the R1 and R2 scales, which afford greater precision in working with squares and square roots than an A scale.

I picked up this slide rule for a song in an antique shop in Decorah, Iowa. I just walked in, and there it was, in a glass case along with several other slide rules. Only problem was, the Versalog was missing the little cursor glass on the back side. But I ordered a spare part from Walter Shawlee's Slide Rule Universe out in British Columbia.