If you're going to be White and Nerdy, you might as well go all out.
This insert fits into standard amazon eyeglass cases, and accommodates a Sharpie, a retractable Xacto, a tweaker (screwdriver), and the most high-brow pen pencil and fine marker set money can buy.
By which I mean a Rotring 600 full metal mechanical pencil, Rotring Rapidograph full metal ballpoint pen, and a Pigma Micron archival grade micro-Sharpie.
Seriously folks, if you do a lot of pen, pencil and paper design, treat yo self, and get that triple combo.
The tolerances on this one are really tight, and will require filing/reaming/drilling to get a perfect fit.
Your Rotring set deserves no less.