1. Material: The bolt is made of wood, the stainless steel slide rail is easier to slide, and the ball is made of plastic. Safe and non-toxic.2. Get: wooden frame bolt, number card, 100 counting sticks, and 1 addition, subtraction, multiplication and division table, which can be clearly learned or consolidated.3. Safe and practical design: We polished the edge of the calculator bracket to make it smooth and not hurt the delicate hands of children. The ball board slot can be placed on the digital puzzle to facilitate parents teaching.4. Easy to transport: Our wooden bolts are suitable in size and easy to transport. You can bring a wooden ruler. When you travel, you can take it with you and interact with your children anytime and anywhere, so that children can learn happily. Stimulate their creativity and promote their mathematical thinking.5. Exquisite gifts for boys and girls: parents or grandparents can choose this wooden ruler toy as a birthday or party gift for children. This is a good choice for teaching children to count and learn mathematics