Warnings: Use of magnets during pregnancy should be avoided. Also, strong magnets can snap together very quickly and pinch fingers or cause the magnets to break when two or more come within 4" of each other. Dropping magnets on a hard surface may also cause breakage. Magnetic fields can affect instrumentation, such as: watches, pacemakers and/or automatic defibrillators, as well as surgical plates. If you use any of these devices, please do not maintain close proximity to a strong magnetic field.