Beautiful things. I'm not sure how to evaluate "thickness" or how "transparency" behaves in general, but I have two points that need to be covered. First, the "locking" mechanisms are too long. They are so long that they protrude and can easily be gripped with pliers and thus unscrewed. Second, only pull the caps down hand tight AFTER you apply some oil to the threads. The shape makes it too tempting to use a tightening tool if it doesn't come all the way through after the first tightening. A…