These leather lovelies have a stud fastening and a nifty pen holder.

Another form, the beam compass, has the pivot point and pen holder joined by a bar, useful when drawing very large radius arcs.

For example, a subject may be imagined trying to pick a red pen from a pen holder.

Both the drum and the pen holder were controlled by stepper motors.

The planner may be used in an optional cover with several useful features like card pockets, bookmarks, and a pen holder which doubles as a clasp.