Whiteboard Marker Pinup Cap

UPDATE: Check out the new and improved design here: https://www.thingiverse.com/thing:5496130

Designed this for a You3Dit request. I referenced the cap design/dimensions from kielerrr's Fast-Draw Cap Marker Holder (and bought an EXPO dry erase maker to measure and test with), and created this cap that can be pinned to the wall, bulletin boards, pin boards, etc.

NOTE: As @kielerrr mentioned in the comments section, these caps may not be tight enough to keep the markers from drying out. I'l