Two versions here: 5 hole, 20mm marker holes (fits the standard Expo markers) and a 6 hole, 14mm marker hole (fits the slimmer, click-pen style Expo markers). Both versions have indents on the back where the 1/2" x 1/16" magnetic, sticky tape goes. I used a few drops of superglue to make sure the magnet doesn't come off. Markers point to the left as pictured, but the supplied sketchup files can be adapted to your needs.