Years ago I bought a set of 4 shelf dividers that are wonderful (basically 11" tall by 11" deep, which is a perfect size for my needs) - but of course I can't find them again to buy more. This set of dividers that I'm reviewing is the THIRD SET of dividers (3 different brands/types) that I've ordered from amazon in the past couple of weeks; the first set was useless (no tension at all -- I cannot see how they would work for ANY shelving unless it's the EXACT size as the opening) and I'm returning those; the second will work for other shelving in my house but their "insert" part isn't long enough to be adequate for "latching onto" the shelving well, which made them not work for what I bought them for; and then there's the third set, THIS set, which I think is going to work well.I have lots of boots, as in more than a dozen pairs of tall ones (yes, I'm a bit boot crazed!) plus some short ones. I bought a cheap bookcase to use in the dressing room of the master bedroom as shelving for them (just had to drill shelf holes in different places) -- that bookcase can hold 15 pairs of the tall ones on 3 shelves (shelf space height ~18.5") plus short ones on the bottom and top shelves. But how to keep the tall boots upright and separated? Shelf dividers!As you can see from the photos, these dividers work for my purpose, despite the fact that they're only a bit over half the height of the boots. The first photo shows my first attempt with these dividers, when I found out, YAY, they would work! The second photo shows me started on the 2nd shelf. The third shows how I keep the boots upright between the dividers -- I cut 2x2s to size and inserted them into the boots (gotta get creative sometimes!).So these dividers should work well for my purpose, although I would be worried if I were moving them around a lot -- my shelves are about 5/8" and the dividers fit great (the info on amazon says they can work for shelves between .2" and .9", and that looks correct), but I am VERY gentle when pulling them out as I'm afraid of the acrylic getting brittle and breaking. Alas, only time will tell if that will be an issue.In the meantime, I got 12 dividers at a decent price, so I am happy! I've opened the plastic wrapping on about 8 of them so far and have found no damage -- the remaining 4 looked good too but I haven't gotten to them yet. But it's so nice to see my dressing room getting ORGANIZED -- after 12 years in this house, LOL! :)