These strong neodymium magnets have a protective steel housing and come with detachable, stainless steel hooks for hanging applications. The max pull numbers are measured by pulling the magnet directly off of an optimal attachment surface.
If the magnet is attached to a horizontal surface such as a ceiling you will see a hanging strength close to the max pull number. If the magnet is attached to a vertical surface, such as a wall, the hanging strength will be less due to sliding and tilting.