Maybe spywalk tank zipper (or big zipper) backpack? It seems that the plastic version of the zipper has been discontinued, and the metal version of the zipper is $690, which may be NT (divided by 5 is RMB, I don't know the freight).

I have seen and bought it in my hometown in Zhejiang before, but now I don't have it. It's weird.

If you want this kind of products, I'm afraid you can only go to Alibaba to search for "manufacturer's zipper wholesale 30# oversized resin (injection molding) zipper personalized zipper grooved luggage sells well", find the manufacturer selling this kind of zipper and order a zipper; Find another shop to repair shoes and zippers, and spend tens of dollars to convert them into ordinary backpacks (provided that the ordinary backpacks have a large margin).