In today’s market the Celstir design is the standard flask type for cell culture. Celstir flasks feature adjustable blade impeller for increased aeration and dimpled bottom to prevent the accumulation of cells under the impeller (dimpled bottom on 125 mL size and larger). When used with the Micro-Stir®, which can operate at very low speeds, the Celstir flask provides an optimum environment for most suspension lines, including insect cell cultures. Hybridomas and adapted cell lines can also be grown in these spinner flasks. Sidearms on Magna Flex® and Celstir vessels 500 mL and larger were widened to accommodate monitoring and control devices or media inlet/outlet lines. The Wheaton Celstir features an adjustable paddle blade impeller for better mixing. The impeller does not protrude through the top cap, thereby maximizing incubator space and reducing the chance for contamination. The addition of the bottom dimple to flasks 125 mL and larger improves circulation and reduces the accumulation of cells in the center of the flask. Units 500 mL and larger have a 45 mm sidearm to be used as an air vent, media inlet or outlet, inoculation port, pH probe inlet, or for other applications. Celstirs provide maximum surface interface between culture and flask atmosphere. All flasks are proportioned to provide a head space ratio of 1:1 or greater. The unit consists of a glass flask, Teflon® and glass impeller assembly, and Teflon and Silicone-lined top cap. It is designed for use with Wheaton Micro-Stir magnetic stirrers. The entire unit may be autoclaved. Wheaton also offers a non-breakable stainless steel shaft assembly kit as a retrofit to your Celstir (see 356874 series). 1000 mL size is graduated in 50 mL increments. Celstirs are made from 33® low extractable borosilicate glass (meets ASTM Type I Class A and USP Type I Standards). Units 500 mL and larger can be used with the Vented Cap (W240751).