Needle system* : 7X10 Pack Of 50 Groz-Beckert 7X3 DYX3 Industrial Sewing Machine Needles. Also sold under needle system number's : 794H, DYX3, SY5220 Needle Length, butt to needle eye : 60.0mm Shank Diameter : 2.5mm Pack Of 50 Groz-Beckert 7X3 DYX3 Industrial Sewing Machine Needles. Needle system* : 7X3 Also sold under needle system number's : 794H, DYX3, SY5213 Needle Length, butt to needle eye : 60.0mm Shank Diameter : 2.5mm *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. Groz-Beckert 7X3 needles are available in following sizes. Please select the size from the drop-down option menu : Singer Size 19 (Metric Size 120) Singer Size 21 (Metric Size 130) Singer Size 22 (Metric Size 140) Singer Size 23 (Metric Size 160) Singer Size 24 (Metric Size 180) Singer Size 25 (Metric Size 200) Singer Size 26 (Metric Size 230) Singer Size 27 (Metric Size 250) You'll receive 50 needles in the same size. For Singer 7 Class, 34 Class, 144 Class machines and other extra heavy sewing industrial machines including : Tippmann Boss, Tippmann Aerostitch, Adler 205-370, 205-374, 204-370, 204-374, Juki Pro 2000, Ferdinand Bull Artisan Toro 4000.