Concerns
Crib mobiles can present choking and strangulation hazards due to small parts and strings.
Testing
The Consumer Product Safety Commission (CPSC) requires mobiles to be tested to the standard of ASTM F963. This is a toy-testing standard, developed by The American Society for Testing and Materials (ASTM), that calls out a litany of physical and mechanical testing.
Requirements
Some of the CPSC's testing requirements for crib mobiles include, "no strings with loops or openings having perimeters greater than 14 inches" and "no strings or cords longer than 7 inches." Also, mobiles shouldn't have small parts that infants can pull off.
Shopping
When shopping for a crib mobile, purchase it brand-new. Check the fine print on the back of the box for a proper testing label stating "conforms to the safety requirements of ASTM F-963."
Consumer Safety
The CPSC suggests hanging crib mobiles out of your child's reach and removing crib mobiles once your baby can push up on his hands and knees.