The file 'Citadel Paint Holder 3D Printer Model' is (stl) file type, size is 11.3KB.
I machined mine out of Delrin but should work fine when printed. The hole on the bottom is for 3/4" DIA x 1/8" thick neodymium magnet (MCmaster #5862K893).
Citadel_Paint_Holder.stl | 56.1KB |