I don't want to advertise, but I used a vendor on"that" auction site. Just compared the prices between a couple. There are others on the net. I have used both rayon and cotton covered. The rayon is funny, because the fabric sheath likes to get fuzzy where you cut it. I put clear nail polish on it. Then heat shrink over that. It looks right on the older National and New Home machines, and fits in tight spots.