Gauge: Gauge (号数)
The size number that identifies a zipper family by the nominal width of the closed chain, measured in millimetres. Common gauges are 3, 4, 5, 8 and 10; a higher number means larger teeth and greater strength. Gauge determines which slider, stops and end parts fit, so mixing sizes causes jamming or separation. Designers select gauge from the load, fabric weight and visual scale required by the product.