A nice long AlNiCo Rod. 40 years ago these were the strongest magnets you could get, these days they don't seem so impressive but they still have their place! You can cut/machine this material. It is relatively safe compared to NdFeB and other rare earth magnets. AlNiCo also has the highest curie temperature of any magnetic formulation so these are handy for high temperature applications. The rod is roughly 5/16 in x 8 in long and the poles are at opposite ends.