If you are tired of losing wire spacers while winding,, these o-rings are 3D printed from a hard epoxy resin. They will NOT twist.. Dimension are 0.140” OD x .060 ID and weigh appx. 0.006g each. they come in a string from the printer, you just cut the joining legs off with a razor blade and you are ready to go. If you still need to use the wire spacers, you can hook them on AFTER winding