This magnetic building tiles Made of food grade ABS plastic and strong magnet. Smooth surface, round edge design won't scratch or hurt hands. Using ultrasonic welding process to ensure better tightness, rivets on the edges for double protect, so magnet won't easily fall out, durable for long-term use. 
Good to develop kid's variety of abilities. Perfect preschool toys. Your kids will freely apply their imagination and creativity to build variety of models and constructions like animals, trees, castles,...etc. Let them enjoy the boundless fun of the magnet building toys!