Schmetz has color indicators on their home sewing needles that tell you what type of needle it is and its size. Download the guide here!
2 or 3-needle Industrial Stretch Sewing Machine Rule, Seam Guide
Needle Guide – SCHMETZneedles
Sewing Machine Needle Color Code Chart – SCHMETZneedles
Singer Sewing Machine Needles - Choose the Right Needle for Your
Blog - Sewing Resources from WAWAK Sewing Supplies
Brand New Style 30pcs Domestic Sewing Machine Needles 3 Sizes 14
Amann Saba Thread Color Chart
Complete Guide to Sewing Machine Needles - The Cajun Girl
SINGER® Needles - SINGER®
30PCS 5 Sizes Big Eye Sewing Machine Universal Stitching Supplies
SCHMETZ Needles USA Blog : Sewing Machine Needles: Color Coding