This is a JAW HARP. It’s also known as a mouth harp, trump, juice harp, vargan, or ozark harp. They are thousands of years old. This particular one is made of metal but they are also sometimes made from bamboo or other light woods. You play it by placing the frame against your teeth and plucking the spring. By changing the shape of the inside of your mouth, you can make sounds and harmonics. Are they a toy? Beethoven's teacher, Johann Albrechtsberger, wrote several pieces for small orchestra and