Cell culture flasks are specifically designed for successful growth and propagation of microbial, insect, or mammalian cells. Most common varieties include flat-sided tissue culture flasks, Erlenmeyer flasks, and spinner flasks. Cell culture flasks are typically manufactured from borosilicate glass, polystyrene, or polycarbonate, depending on the application, and are available in a wide range of sizes. A variety of closures are available, including vented and unvented screw caps.