1. Check with your doctor if you have any injuries or medical conditions before using Neck King® or The Back King™.
  2. Stop using if you feel any numbness. This could happen if you stay on the bumps in one spot for too long.
  3. Do not sleep on Neck King® or The Back King™.
  4. Do not work the area just below the back of the skull aggressively. This area can irritate cranial nerves more easily in some people causing numbness or a delayed numbness. Start with minimal use in this area to make sure this isn't a problem for you.