The "children's" version—mine—is made of plastic, without external corners or edges. The sound is dull, quiet, and short, but with deliberate playing it's perfectly possible, as the coloring doesn't drown out the overtones in a controlled context. The instrument is fragile and easy to squeeze with the lips, and even with the hand, to reach the reed against the frame, but it has a wide turn, making it a fun and safe pastime.