Bel-Art F37110-0112 Stirring Bar.  38.1mm (about 1.5″)  x 8mm.

Use this in combination with an Erlenmeyer Flask and Stir Plate to make a yeast starter.  A stir plate… keeps yeast in constant contact with nutrients, encourages CO2 to off gas and continuously incorporates oxygen.  All of that means higher cell counts.

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Bel-Art F37110-0112 Spinbar Teflon Octagon Magnetic Stirring Bar; 38.1 x 8mm, White

Also: Yeast Starters & Fermentation Resource Page | StirStarter Stir Plate | Yeast: The Practical Guide to Beer Fermentation

Higher Cell Counts, Decreased Lag Times, More Vigorous Fermentations, Great Warranty StirStarter Stir Plate – Hands on Review!