1. It is made of 304 stainless steel, with one-piece thickening design, reliable structure and beautiful appearance. 2. Multi-point supporting structure, more reasonable transmission system, flexible operation, low failure rate 3.5% . The Hand Zipper disc cover adopts special curling process to ensure that even when the hand zipper is inclined and pulled horizontally, no chain clasp is produced 4.5% . The hook is forged with stainless steel, strong and durable, the whole machine has good anti-corrosion effect 5.5% . The product is suitable for the occasions of chemical industry and the occasions with higher clean requirements