These are 18cm Balinese cymbals called Ceng Ceng. Traditionally made from bronze, these are made from sheet steel, a lighter metal, and are perfect for children to use to accompany Gamelan. To plat them, hold one in each hand and hit them together. They are designed to produce a dampened sound rather than a clear resonant sound like Western orchestral or band cymbals. These are for making rhythmic clashing sounds more than elongated shimmering decays.
Product details: https://www.drumsforschools.com/product/ceng-ceng-18cm-pair/