1. This rule was produced for Shell
2. The scales on the rule use the same font and markers as the Concise 28 but the scales are not the same.
3. The tables and formulae suggest an orientation to physics and chemistry. In addition to the two tables shown and common ones, such as conversion factors for distance etc, other tables include gas constants,energy and pressure.

My thanks to Wayne Dawson who provide the images of this rule.