144 L size plastic-sided bobbins BLACKWe digitize and test stitch embroidery designs - a lot of them. Afterdoing a simple calculation, we realized that it is cheaper to use prewound bobbins (not mentioning the saved time & frustration). These prewound bobbins include the largest possible amount of thread per bobbin, as they have no sides and this free space is taken by extra thread. These ThreaDelight ™ bobbins are champions, both for price and quality.Excellent prewound bobbins for home and professional use.