This are new old stock. Finding information about these bobbins is a bit challenging. These have brass ends and a steel (?) center post that peeks out either end. We have different lengths in this style. The diameter of the ends of the bobbins are 5/16" (8 mm). They measure 1 1/4" (32 mm) from blunt point to blunt point. The inside measure is 1 1/16" (27 mm). If you do not have a vintage sewing machine you may still want some of these bobbins! There would be great for mixed media projects or even jewelry!