Shelf dividers or something I have seen and contemplated buying for years but for some reason, I always thought better of it. These happened to have been on sale a few weeks ago, so I picked up a couple of sets and I have to say, I am thoroughly glad that I did. Already, they are giving structure to my jumbled up, very limited closet space and I have deployed them so far in my linen closet, my pantry, my supply cabinet, and the storage where I keep my tools.I am glad to have finally bit the bullet so to speak and purchased a set because they are subbing storage issues that I have had and been trying to resolve for many years here in my apartment to varying degrees of success. These are very sturdy, align perfectly with the shelves while not prohibiting cabinet doors to close flush, and, there's not much else to be said other than the fact that they do what they are supposed to do, and do it well. I am definitely ordering a few more sets.