Fixed string. Erhu metal ring is a small metal piece in Erhu accessories, which is usually used to fix the strings so that they are not easy to fall off. As one of the core components of erhu, the installation and maintenance of strings are very important, and the metal ring plays an important auxiliary role. The use of erhu and the playing of chords require frequent replacement and adjustment of strings, metal rings and other parts to ensure the sound quality and playing effect of the instrument.