Raised Magnetic Stir Bar - 2 cm
Use this magnetic bar to stir a yeast starter with a stir plate. This method allows for constant stirring without having to pick up your flask.
Just drop the stir bar into your starter flask, and place it on top of your stir plate, and it will spin on the bottom of the flask, stirring the starter.
The raised ridge in the center allows it to spin much more freely, with less friction on the bottom of the flask.