A friend needed a way to carry a USB-C adapter just in case her phone needed charging. She was using a binder clip on her key ring. Wanted to protect from dust and damage in pockets or hand bags. Seemed logical, may have to devise an attachment method but for now this is what I could do in the time I had. Have 8mmx2mm rare earth magnets so that is what the embedded magnets get glued into with a drop of crazy glue. The key ring is standard for me as I acquired a bunch years ago and still working through them. It's a 28 mm ring but any similar size will work. Holes are large enough for paracord as well it that is your thing.