In the apparel industry, the quality of a garment is often judged by its smallest unit: the stitch. Selecting the incorrect stitch class can lead to seam failure, poor elasticity, or fabric damage. This guide categorizes the six essential stitch classes as defined by the ISO 4915 international standard. The Three Methods of Stitch Formation Before selecting a class, you must understand how the thread is manipulated: Intralooping: A single thread passing through its own loop (