1. Trig functions are done in PIC's patented method which uses less space but requires more cursor movements.
2. It also has differential log-log scales which avoid the use of LL1 and LL0 scales found on some rules.
3. A copy of the instructions for use can be found here.
4. This was my own rule and it served me well at school, university and the early years of my professional career.
5. For an article on the "differential" trig scales see the article by John Mosand (Two Unusual Types of Trigonometric Scales) by John Mosand in the Journal of the Oughtred Society, Vol. 9, No. 1, Spring 2000.

Front view

Differential log-log scales

Differential trig scales

Differential inverse trig scales