Using As A Ruler - Westfalia 83 65 91 Instruction Manual

Measuring
acute angles
 If you want to measure acute angles, open both rulers
completely and place them on a flat surface. Make sure
that both rulers touch the surface.
 Press the zero setting key. The display shows 0.000.
Rotate the rulers and measure the angle. Read the
measured value on the display.
 The zero setting key (7) can be pressed at any time to
reset the display to zero.

Using as a Ruler

On both rulers a metric scale and an imperial scale are
printed. This way you can use the device as a ruler.
Operation
14