1. Although fairly complex, this rule does not have log-log scales.
2. It was intended to provide some commercial functionality. This is shown by the K (capital), Z (interest), T (time in days) and p% (percentage) markings. The cursor also has has a "360" marking. This implies that daily interest rates are normally based on 1/360 of the annual rate and not 1/365. This line can be seen on the detail of the cursor. When the main line of the cursor is set against the 1 on the D scale (labelled 1) the small "360" marking is against the 360 on the DF scale (labelled 2). The cursor also has another small line for use with the CI scale. When the slide is aligned so that the 360 on the CI scale is against the main cursor line, this small line line is aligned with 365 (labelled 3). The documentation implies that it is only in "judicial accountancy" that a year of 365 as opposed to 360 days is assumed.
3. As with some other late manufactured Faber Castell rules, this one suffers from ink bleeding from the scale markings into the stock.
4. This is one of the few rules to have two sin scales, one on the stock and one on the slide. This facilitates some trigonometrical calculations.
5. This rule was purchased via the USA and came with a leather effect holster. Whilst these were common in the USA they were not often seen in Europe.
6. The number of this rule differs by one digit from the 52/82 yet the rule is very different. One wonders why makers never seem to have developed a rational numbering system.
7. Some of the functionality of this rule is reproduced in the Nestler 7/52. With reference to the above comment, is there a "rational" explanation for the "52" appearing on both rules.

Detail - cursor