3 Pack, PTFE Octagon with Pivot Ring Magnetic Stir Bar Set - 50mm / 1.96 Inch

These are well made and larger than I imagined, even knowing the dimensions! I purchased the INTLLAB magnetic stirrer, which works very well, and also purchased these bars. I didn't understand at the time that the length needs to be close to the length between the centers of the magnets in the stirrer, but that information isn't provided by the seller. These work a little bit, but only at a very specific slow speed. When the speed was increased, they broke the magnetic bond and rattled around. INTLLAB included a 25mm x 7mm bar that works great up to full speed! It was my fault for not understanding.

Used for 4 liter yeast starters. This is really nice. Whirlpool down 4-5 inches and allows me to run full power. One seems to be a little off balance but usable. The other 2 are perfect.

Far less friction than other stir bars. Easier on the stir plate motor and less heat build up too. I make a lot of yeast starters and these are my choice.

First test - anything above 25% speed and they fly off. You have to approach the speed very slowly. Over night - it still flies off. Reduced to 20 then 15% .. and at 15% power it is stable - but cant mix the fluid.

These mix the liquid faster and with less noise than the shorter bars I've used. Not unbalanced as one reviewer said, it often depends on how centered the bars are on the magnetic stirring plate (particularly home-made plates).