I was playing with little bits today. They are a really cool piece of equipment that can be assembled to make a keyboard and a synchronizer among other things. In a K-4 setting, I'm afraid the system might be too delicate for a makerspace unless it was just placed ready to go when older students are in the library. There are wires and such connected but different contraptions are assembled by magnets on the parts which is super easy. The little guide books clearly labels and guides you through the process. I know nothing about the science of sounds and circuits but I definitely feel like I know more now. :) Here's a pic some of the pieces by my finger so you can see the general size.