Well, plastic at least. I can remember studying one of these at around age 4 and working out how it functioned, prompting me to disassemble a couple music boxes of my mom's to see if they worked the same way (similar, but using a drum). I also remember getting into a bit of trouble for not putting them back together. What can I say, they were far more interesting with their inner workings exposed. Builder jtheels nails another retro build (and brings back all the childhood feels) perfectly.