Yep, you can definitely stack the Stanley STST14021 organizers. Based on what the manufacturer says, they've got this special lid design that keeps everything inside from moving around, making them great for stacking. They’re made from tough plastic and have locking latches, so they should stay secure and be easy to stack up.

Heads up though, each organizer can hold up to a maximum of 10 pounds. Our research suggests sticking to this limit to keep them in good shape. If you pack more than that, you might run into issues with durability and functionality.

As for build quality, folks often give these organizers a thumbs-up for being robust and sturdy. They come with removable dividers too, which is handy for customizing how you organize small parts and tools.

So, in short, stacking these is no problem. Just respect that 10-pound limit to make sure they last and stay in good working order.