What does Tian 999.9sp mean?

Silver purity. Gold is divided into thousands of pure gold and pure gold, marked as: au999, SP999 is thousands of silver, indicating that the purity of silver is 99.9%, so Tian 999.9sp indicates the purity of silver. Metal elements. The symbol Ag is white and shiny, so it was called "platinum" in ancient times. It is soft, malleable, good in electrical and thermal conductivity, stable in chemical properties and not easy to oxidize in air.