I use this to teach kids that some things are within their control (Play-Doh problems) and some things are not (rock problems). I give them a set to take home as a reminder. Throughout therapy I'll often ask, is that a rock problem or a Play-Doh problem? It's one of my favorite tools.
I used an old Kleenex box and covered it with duck tape. You can use whatever for the counting. I used cotton balls (20) and then when a student is starting to throw a fit or having a hard time following directions you have them dump out the 20 items and count them as they put it back in box until they calm down!!