WonderFil pre-wound bobbins are wound with our 80wt DecoBob thread in a reusable plastic bobbin, which means there is no glue or wax holding it together making it machine friendly. These bobbins has a fine weight thread which minimizes any bulk in whatever you are doing while providing strength, versatility, and reliability that you can count on. These also offers more consistency in all your stitches making it a great choice for your threading needs. They also come wound with a higher density of thread than when you wind your own bobbins on a domestic machine. Plenty of sizes and colors are available, choose your desired color and the ideal size for your threading needs!