These large grommets are gold-plated brass to assure a good electrical connection, keep them from corroding and allow for easy soldering. The large grommets are recommended for use with tape wire in your dollhouse to make a better connection, and they are the more preferred size over the smaller grommets. (110 pack)
Watch #700 BamBam Spring Tool video tutorial to see how to use the grommets, tape wire, and BamBam Spring tool to connect the electricity in your house. https://cr2s.com/video-tutorials/