3mm to 5mm LED Adapter

thingiverse

A very simple adapter to help a smaller 3mm LED fit into a 5mm LED holder snugly. Plus, if you are using a white led, you can color the light being emitted however you'd like! Use a semi-transparent or fully-transparent material to ensure that the light from the 3mm LED passes through. Because the wall is going to be relatively thin, use the highest resolution printing settings possible. It's a small object, so the print time shouldn't be terrible.