If you work with wires for work or hobby, you sometimes need to keep certain functions or connections clear as you're doing your thing. I often use a piece of tape or a label which invariably dries out and falls off. This small tag will hold snugly to your wire and take a stick-on label in a recess, or you can just write on it with a sharpie marker.
I'm sharing three sizes that allow you to accomodate a variety of wires. The sizes are 2mm, 3.5mm and 5mm. They use very little material and print quickly, so you can try a few and see what works for you.
They seem to hold snugly and won't get knocked off the wire, even if the wire is a bit small for your chosen tag.
No supports required - they seem to print fine as is. A bit of clean up with a knife or sand-paper will help after you're done.