This product is a serum-free and chemically defined medium developed for protein expression HEK293 cells (293T, 293S, 293E and 293F), suitable for continuous culture of 293 cells and transient expression of exogenous genes. This product is suitable for high-density expansion and continuous and stable subculture of HEK293 cells and efficient expression of exogenous proteins. The HEK293 cells transfected in this product show excellent transfection efficiency.