“Can I have a new pen for my Promethean board, I've lost my old one”.
Ah, the usual weekly service ticket; another lost pen which needs to be replaced.
Why not replace it with something relatively quick to print, cheaper than the original, and rather fun at the same time?
Introducing the AP9-Compatible Crayon, complete with matching paper label:

I printed mine in PETG as that's what I had to hand, but PLA is a perfect material for this sort of print (it will be softer on the panels too).
I'm going to experiment with adding a teeny dob of hot-glue to the top of mine, as this may further reduce the risk of scratching your shiny panels.
After printing, you may need to trim off any excess plastic from the top of the print; I just use a pair of flush-cuts, and sand down any sharp edges.
The crayon is fully pen-compatible with the screens, just use it as you would a first party stylus. The rear of the pen is also usable as an eraser on compatible boards.
Of course, your crayon wouldn't be complete without a matching label!

The author marked this model as their own original creation.