Twin Stretch Needle Size: 75/2.5mm German-Engineered Steel Machine Needles 1 This type of needle is ideal for heirloom embroidery and is excellent for decorative sewing and topstitching. The size indicates the distance between the needles. Since the needles are fixed in a block of nylon, use it at slower speeds and do not stop for extended periods of time. With a design Unique curve in the clearance-above-the-eye "drops" distributes pressure evenly which makes Klasse knitting needles tension much stronger than other conventional flat needles