This listing is for one pack of 1 set of Schmetz twin/double STRETCH needles in 4/75. It's essential for when sewing knit or stretch fabrics. The distance between the two needles are 4.0mm. Both needles are of size 75/11.
Double needles are actually two needles mounted on one shaft used to create two rows of stitches simultaneously. Use two spools of thread and one bobbin thread.
Schmetz is world's top brand in sewing machine needles. You can trust the quality and have full confidence in it.