Good smellproof bags without zippers, or with zippers that wont brake

Over the years, I have found it incredibly handy to have a small, portable stash bag. The issue, is that every single one of them the zippers both break, and then it wont close.

Basically every product has a zipper, and when I look in the comments there are many reviews saying the zipper is the weak point and will break.

Anybody know of a high quality one that should last me years without breaking? I would like it if I could avoid zippers entirely but if thats not possible, hardy zippers is what I'm after.