This product is a specialized serum-free medium with clearly defined components and stable performance, specifically designed for the cultivation and functional optimization of mouse embryonic feeder (MEF) cells. It efficiently supports rapid proliferation and optimal condition of MEF cells, ensuring sufficient secretion of essential growth factors and formation of high-quality extracellular matrix. This provides a robust, uniform, and standardized feeder layer foundation for the undifferentiated growth and long-term stable maintenance of high-value stem cells such as human embryonic stem cells and induced pluripotent stem cells, comprehensively ensuring the reliability and reproducibility of related cutting-edge research.