Aristo 915 Elektro

Note

This rule is made with all plastic structure, suggesting that this rule was made at a later phase of the slide rule history.

Sin scale is keyed to C/D scales with additional ST scale. Also, "self document" for ST scale says "arc". All of those features are for "modern" rules.

One other feature of this rule is rubber feet placed on lower side of the rule. They would tilt the rule up on the lower-end. I am guessing that that the purpose is to make it easy to flip the rule by creating a gap at the lower end of the rule.

It has a "little brother" Aristo 815 Elektro which does not have LL2, LL3 scales.