Cloth tape: Since the raw material of metal zipper tape is composed of polyester thread, suture, core thread and other different types of thread, their weight and coloring are different, so the color difference is likely to occur on the same zipper. When choosing the cloth tape, you should choose the cloth with uniform dyeing and no turbidity. The cloth tapes made of different fabrics are mainly soft to the touch.

Microphone: The metal zippers are also electroplated and colored, so you must pay attention to whether the surface is evenly plated, whether there is any coloration, and whether the zipper is smooth when you pull up and down. After the zipper is closed, it must be observed whether the left and right teeth are engaged with each other. Asymmetric zipper teeth will definitely affect the use of the zipper.

Pull head: The metal zipper pull head has many shapes, and the finished product can be small and delicate, but also rough and strong. But no matter what kind of slider, you have to feel whether the slider is free to open, and whether the zipper can't be pulled up or closed. The sliders on the market all have a self-locking device, so after the zipper is closed, it is necessary to check whether the zipper will slide down after the lock is fixed. Limit code: The upper and lower stops must be tightly fastened or clamped on the microphone teeth, and must be strong and perfect