I bought a few boxes which have this normal standard seize (60x40cm). When I saw these dividers by Thon I ordered three packs of them to make every box look more clean and organized. Of course, there are other dividers as well, but now for this price.
The only thing that I do not like about these dividers is the height. I use boxes with 20cm height and boxes with 40cm height. For the 20cm version, these dividers are a bit to high, which means you cannot stack a few of these boxes. For the 40cm boxes the divider's height is not perfect at all, because they are not high enough either.
But because these dividers are made for the red Thon boxes, I do not count stuff like this.
In total, these dividers are handy, easy to use, flexible, and of course; nice to have :)