Needle system* : 29X3 (DIX3) These needles also cross to these different needle systems : 332, DIX1, SY3741 *A needle system is a group of needles made to fit specific sewing machines. All needles in a system are of the same length and shank size, but are of various diameters. Lower size numbers are narrower or thinner needles used for lighter materials. Higher size numbers indicate a needle of thicker diameter, used for heavier materials. Match your needle system to your machine, then the size of the needle to the product you are sewing. You'll receive a box of 10 packs of needles. Each pack contains 10 needles. Total of 100 needles.