I found these at the dollar tree. I am probably going back today to get some more! They fit the CTMH stamps really well. However - they won't be able to stack if you have the stamp sets standing straight up. But if you don't fill the box completely and let the stamp sets go back a little they work great. I still love my CTMH box with the handle for when I am traveling with my stamps - but these are great storage for stamps you don't take with that much (like seasonal). I also like to keep the one on top to put in the stamp sets that I am currently using - so I have a place to put them, but don't have find them in the other boxes. For only $1 who can resists?