This is a simple 4 marker holder to keep your EXPO markers vertical and off the tray on your whiteboard. It uses 4 12 mm x 2 mm round Neodymium magnets. I just use a small dab of super glue to hold these in.
The inset for the magnets is chamfered and should print fine w/o supports.
Expo_Marker_Holder_1.stl | 1.4MB |