The most common needle used by professionals, the Topstich needle has a larger eye and a deeper groove, reducing friction and resulting in fewer thread breaks. Depending on what type of thread you’re working with, every size needle has a different specialty: the #70/10 works best with very fine threads (60 wt), the #80/12 with fine threads (50 wt), the #90/14 with medium threads (40 wt), and the #100/16 with heavier threads (30 wt and heavier). The Assortment Pack is a perfect variety pack of each needle size for all your sewing needs.