When you built your Eggbot ( http://egg-bot.com ), were you disappointed that the default pen arm wasn't large enough to accept the ubiquitous fine point Sharpie marker? I know I was (especially since I had just bought a pack specifically for my new Eggbot).This model is a replacement pen arm for the Eggbot, designed to accept Sharpie fine point markers (of course, anything smaller in diameter will fit too!).I printed with a Maker Bot TOM (with ABP) with the following settings:1.75 mm ABS plastic .4 mm extruder diameter Extruder temp of 125 No raft Platform temp of 120 C (important for ensuring that the print doesn't curl when using the ABP) 3 shells (may want to bump it up to 4, if you like) *15% fill .3 mm layer heightAfter printing, I'd recommend putting in the screws first, then removing them to "thread" the holes, before you fasten it to your Eggbot (it takes a little elbow grease as the holes in the model are smaller than the screws to ensure a firm grip).Then remove the nut from your default Eggbot pen arm and insert it into this new arm. Put in the thumbscrew, a marker, and you're good to go.