Many applications for magnets require a matched pair for purposes of attraction. All magnets have a north polarity, and a south polarity (on the opposite side), but the poles are usually not distinguishable without some effort. Proper pole alignment is critical during assembly, as incorrect orientation will result in repulsion rather than attraction. To solve this problem Bestway Magnet stocks Magnet with Mark. Usually this is a red dot, or small red line on the north seeking side. During alignment all that is needed is to ensure that two magnets are not showing the same surface (blank/blank) or (marked/marked) as this will result in repulsion. Proper assembly for attraction would be marked & blank together, as this represents a N-S attraction.