I use the little white circles that are actually for reinforcing 3 ring binder holes in paper. I can label them with any pen/pencil I have handy. I like them because they only cover up the end of the bobbin (and I can tuck my thread in them so the bobbin doesn't unravel) so I can still see the thread color. The only thing to remember when using these is to touch the sticky side to my pants a couple of times before putting one on for the first time because they are pretty sticky.