I made a small hole in Joel Tellings design ( http://www.thingiverse.com/thing:1323005 ) and sized it down to 60mm so it fits to my keyholder. Thanks Joel (3D Printing Nerd) for this nice design. Printer: Da Vinci 1.0a with E3D V6 hotend Rafts: No Supports: No Resolution: 0.2 mm Infill: 15 % You can add  pauses (M0) into the gcode to switch colors.