I use them for LEGO bricks. They are light and flexible, especially suitable for small pieces, large ones (from 8 by 8 studs) don't fit in. The price is not too high either. Comparable boxes that I have found were more expensive.
Practical, flexible and stable Dividers must be at the bottom so that the lid closes properly and it is better to place the smallest items at the edge so that they do not fall out in the middle.
Stable and good product