I have tried other bobbin holders in the past but I think this one is by far the best for keeping the bobbins attached to the spools. When in a spool of thread, they still fit upright in a thread drawer that is 3-1/8" deep and my 2-1/2" spools with the bobbini still fit nicely on my spool holders (with a vertical rod of 1-1/8" high). My shorter spools of thread (1-3/8"), with the bobbini, will not sit on the spool holders as there is no room inside the thread spool so my solution is to keep the shorter spools in the drawer. I would recommend this tool!