Inside the pace is is a metal bar with measurements in inches.
If i am not wrong there is 12, 24, 36, 40 inch marks.
Every mark has a notch where you "hook" it on to other side of the
stick. This way, the pace stick opens up locked to the measurement
you want.
Also, the pace stick is issued to Companies and Battalion not the
personnel holding the appointment. Meaning, CSM's pace stick is a
company asset not his personal issue.
If I am not wrong, only WOs are given Pace stick like how Officers
are given the swords.
For your own interest, Pace sticks are traditionally used by
Artillery corps for gun emplacments (distance between 2
guns).
In SAF, it is used to symbolise the CSM/RSM.