This is a Wire Grommet printed out of TPU to block the light that escapes from your light box. Makes for a finer finished product. This one fits round holes that require a 20mm Grommit. Like DylansLightBoxes. Has a 4mm hole for the wire. You can also resize in slicer. Print with 5% Infill and 1 top & 1 bottom layer so you can cut one end of the grommet so the wire can slip into it. then push or glue it in place.