Fil-Tec Magna-Glide Delights 120x2 High Tenacity Trilobal Polyester No. 40 Tex 27 Prewound Bobbins. The magnetic core rotates the bobbin consistently throughout the entire bobbin which results in uniform tension to the last stitch. Consistent tension throughout the bobbin increases stitches per bobbin. This equates to more time quilting and fewer bobbin changes. No backlash or overspin issues.