This polarity checker consists of a cylindrical, grade 35 neodymium-iron-boron magnet encased in a break-resistant plastic tube. The biomagnetic North pole is clearly marked and is at the end of the tube. By checking the attraction or repulsion, the polarity of other magnets can be determined. A similar item was marketed in Japan as a drink stirrer which was reported to make beverages more mellow through the effect of magnetic polarization. We have found that most people can, in fact, taste a difference in coffee, tea, etc. after stirring for 15-20 seconds with this magnetic stirrer.