Fil-Tec Magna-Glide Classic Prewound Bobbins L-Style 67×2 High-Tenacity Polyester Filament No. 60 (Tex 12). The patented magnetic core creates consistent delivery throughout the entire bobbin. No more interruptions for tension adjustments as your bobbin gets smaller. Magnetic core prevents backlash or over-spin and eliminates the need for backlash springs. Magna-Glide is the original high-yield magnetic-core bobbin. 100 White bobbins per box/135 yards per bobbin. FILTEC Can be used in Bernina E16