Schmetz Universal Needles are a general purpose needle that can be used on knit or woven fabrics. It will do a number of tasks sufficiently. It has a long scarf that is great for zigzag stitching and it does not damage knits. It is sharp enough to go through many fabrics but it does have a slight ball point, so it is not ideal for going through many layers or high thread count fabrics. Twin Extra Wide Size 100/6.0 1 pc- Two needles mounted on one shaft, used to create two rows of stitching at the same time. Use two spools of thread and pass each thread on a different side of the tension discs and thread one thread one into each needle. Only one bobbin thread is used and the stitches create a double web of stitches on the back. Must use with a zigzag stitch plate.