Hello, I am wondering what these modern hookless repro zippers are made of. It was supposed to be a brass, but after just a few weeks of using it is turning out white. It also appears to be wearing off quickly. I was expecting to get a solid brass zipper, which would last for years, but now.. i'm concerned. I would appreciate if you guys post a photo of your hookless zippers after 1-2-.. years of use. Thank you!