1. As the name Mannheim suggests, this rule has a basic set of scales.
2. The left brace seems to be set at an angle, however all the scales align accurately so this may be a design feature.
3. This rule has a sine scale from 35' to 90° for use with the A scale and tangent scale from 5° 35' to 45° for use with the D scale.
4. The rule is all metal.