TST Golden Key Series is the highest-end anti-wrinkle skin care product series in TST brand, with 30 patents, including 4 in Korea and 4 in the world. This shows that this series of products has invested a lot of resources in research and development and has a high level of science and technology. This series of products are suitable for sensitive skin, with refreshing texture and good fluidity, and are quickly absorbed after application without being sticky.