The Consumer Product Safety Commission (CPSC, Commission, or we) is issuing a rule establishing requirements for magnet sets and individual magnets that are intended or marketed to be used with or as magnet sets. As defined in the rule, magnet sets are aggregations of separable magnetic objects that are marketed or commonly used as a manipulative or construction item for entertainment, such as puzzle working, sculpture building, mental stimulation, or stress relief. Under the rule, if a magnet set contains a magnet that fits within the CPSC's small parts cylinder, each magnet in the magnet set must have a flux index of 50 kG\2\ mm\2\ or less. An individual magnet that is marketed or intended for use as part of a magnet set also must meet these requirements. The flux index is determined by the method described in ASTM F963-11, Standard Consumer Safety Specification for Toy Safety.