For when you throw away your broken light bulbs with their base before finding the replacement bulbs. Only to learn that they don't come with the base needed to plug them into the string.I printed this in a RepRap Prusa i2. They don't look pretty, but they do the job after pushing a needle through the wire holes at the base. This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/aq9XFlSVjFc to adjust to your light set and/or printer.