Concise 300

(Click for a larger image)

A nice little duplex log-log circular slide rule, the Concise 300 is a 4.5" diameter plastic disk with independently-rotating disks inset into both front and back surfaces.

Scales:
Front: K, A, D, C, CI, B, L.
Back: LL3, LL2, D, C, S, T1, T2, ST

Back