This is a simple holder for a series of magnets in order to make a Halbach array. Halbach arrays negate the magnetic field on one side and enhance it on the other. I used simple little 15x6.5x3 rare earth bar magnets from amazon. I glued two magnets together at a time to make a square and then inserted them into the holder. You rotate the square magnet with N pointing at 12:00 - 3:00 - 6:00 - 9:00 until the holder is full. Then glue them all in place.