High-efficiency, large-volume culture flasks allow cells to show strong viability with large expression amount of proteins in the culture of mammalian cells and insect cells. During the culturing process, the use rate of the shaker is significantly increased, and the survival rate and viability of cells are both dramatically elevated. NEST culture flasks also provide high repeatability, which allows highly inter-batch consistency of cell growth and yield. 3 L Wide-mouth Efficient Erlenmeyer Flask The bottom diameter of the 3L wide-mouth high efficiency erlenmeyer flask is consistent with that of the 3L high efficiency erlenmeyer flask, and its mouth diameter adopts the neck size of the 5L high efficiency erlenmeyer flask, which not only saves space usage, but also increase oxygen flux, so as to increase the efficiency of cell culture.