This heat resistant borosilicate glass Reagent Bottle with cap is heat rated to 260° F. and is autoclavable. Use just like an Ernlenmeyer Flask to culture yeast, although the bottom is not flat enough to use with a stir plate. The 45mm lid opening fits a 6.5 rubber stopper, or Q38 Foam Stopper. Also very useful as a storage container for autoclaved wort, to be used in future yeast starters. Works with all stir plates. 9" tall, 4" wide.