Thomson Optimum Growth™ Flasks (patented) for mammalian and insect cell culture come in multiple sizes of 125mL, 250mL, 500mL, 1.6L, 2.8L and our popular 5L. They are superior to traditional shake flasks due in part to the fact that they support a 50-60% fill volume versus 33% fill volume making your shake cabinet a much more efficient space.