1. This rule was produced right at the end of the slide rule era and is one of the few all plastic rules produced by Unique.

2. It has a rather unusual complement of scales. The only trig scale it has is sin and tan for small angles, 0.6° to 5.75°. I had assumed that my rule had something wrong with it and that perhaps the other trig scales should have been on the back of the slide but Peter Hopp's book only mentions the scales that this rule has.