CM is the mold code of Chow Tai Fook products in Hong Kong, which means that the design, manufacture, production and sales are all in Hong Kong, and the mainland version starts from ZM!

999 gold means pure gold, which means that both color, purity and craftsmanship have reached the highest level of jewelry. Its logo is usually: thousands of gold, 999 gold, 24k gold, Gold999 or G999. Now the national standard only defines 999 thousand pure gold, which means 999 gold is the highest purity gold.