Children's percussion instrument manufacturers are divided into two types of percussion instruments with fixed pitch and without fixed pitch. The combination of percussion instruments without a fixed pitch is not out of order. Generally based on four categories. Leather: various drum musical instruments. Generally there are resonances, the voice is low, and the volume is louder. Wood: single sound tube, double sound tube, wooden baton, wooden fish, frog box, etc., the sound is crisp, bright, without continuous sound. Dispersion category: sand hammer, sand ball, string bell, the sound is characterized by low volume, scattered sound, and continuous long tone. Metals: triangle irons, touch bells, etc., characterized by a continuous sound and a very crisp sound.