SP Bel-Art Spinbar Rare Earth Teflon Octagon Magnetic Stirring Bar; 2.54 x 0.95cm, Green (F37102-0138)

Can't tell you how many times a subpar stirbar has failed me. This guy is the gold (or maybe rare earth) standard. I love this product due to its superiority over any of its competitors. It is way stronger magnetically than the common ones. It always works, I have not noticed them to weaken, and I have not had any issues with the dyes leaching or anything other than an inert stirbar. Not only would I recommend this product, I exhort it to people.

DO NOT BUY THIS PRODUCT. AMAZON SHOULD DELIST IT. We purchased one, and it was weaker than any stirring rod magnet we have ever purchased. It could not stir at ANY speed, on any stirring unit. It had clearly been demagnetized. We purchased another, asking to return the first. We returned the first, but got no credit for it, it appears to have "disappeared". The second one arrived as a replacement, and it was slightly more magnetic, still less than any of our conventional stirring rods we are currently using. We could get it to stir for short periods at the lowest speeds in water, but not anything more viscous or at higher speeds or for more than a minute or so. Again, demagnetized, ASSUMING it is actually a Rare Earth magnet. We even doubt that. We are going to have the one we own tested to see if there is anything fraudulent occurring here.

A very strong magnetic bar for stirring. Was the only thing so far that has been magnetically strong enough to stir certain heavy solutions at even the minimum stirring speed of 250 rpm (and now higher) without spinning out. Pretty green color. Has a well-rounded and low-profile pivot ring vs other brands’ pivot rings, which I’ve found is nice for ensuring minimal spin resistance and/or spin outs, and for reducing clacking.

The magnetic is too small to spin/agitate liquid even in a 50ml flask.

I don't know why these extremely expensive stir bars seem to be of such low quality. The bar I received cannot hold its own weight against a refrigerator and cannot reliably stir even three liters of water, at anything over 600RPM it spins out and cannot regain stability. Typical cheap stir bars perform well under identical conditions. I read the negative reviews and thought my experience would be different, beware these bars are demagnetized and should not be purchased.

This is definitely stronger than alnico V, but I wonder if it had been sitting in stock stored improperly. It should be stored with an iron cap, or if stored next to other magnets, alternating N-S. It came in a blister card, so I was thinking that if they were stacked next to each other and they all face the same way, then that is the worst way to retain their magnetism. This is a $20 item, so one would think it there would be consideration given to that.

Very strong spin bar for flat bottom glassware I'm sure it could stir 10l with no issue

The quite low strength of this magnet, coupled with its large size, yields a stir bar more likely to perform a lazy spin out than accomplish actual stirring. Useless to me.