Details:

Magcraft Magnets are not a toy and are not recommended for children. 

Ages 14+

These countersunk ring magnets are 0.500 inch (12.7mm) outside diameter, 0.150 inch (3.8mm) inside diameter and 0.125 inch (3.2mm) thick. They are magnetized through the thickness. They are composed of grade 40 neodymium iron boron magnetic material and are plated in nickel-copper-nickel for a shiny corrosion resistant finish. Their individual pull force is approximately 3 lbs. Maximum working temperature is 176 F (80 C).

WARNING: RARE EARTH MAGNETS ARE NOT CHILDRENS TOYS. Practice responsible magnet usage! High-power magnets may cause fatal intestinal pinching if swallowed. Keep away from all orifices. Don't leave them around animals or children who don't understand the dangers. Always communicate these dangers when sharing magnets. If magnets are ingested or aspirated into the lungs, immediate medical attention is required.