MATERIAL: The set uses high-quality, safe and non-toxic plastic. The plastic edges are rounded and smooth without edges or corners, which improves safety and stability. It makes parents safe and makes their children happier.^EASY INSTALLATION: After inserting two AA batteries into the train toy, you can turn on the switch to play (you must prepare the batteries yourself). Domino placement - Insert the domino slot into each end of the slot.^CHILD SAFETY: These plastic domino products are made of non-toxic plastic that is safe and does not fade. The edges are smooth to ensure the safety of children when playing. We do not recommend it for children under 3 years old.^CULTIVATE CHILDREN'S MANY SKILLS: Domino is a leisure activity that encourages creativity and builds self-confidence. It is good for developing participants' intelligence and creativity. More importantly, you can encourage participants' will and teamwork.^HOLIDAY GIFT: This is the perfect gift to stimulate children's thinking. Children can play together at the party and have many happy moments. Parents can also interact with their children. Suitable for children over 3 years old. Please ignore the 6 years and older stated on the product. Thank you for your support.^