1、This cart assembly kit is not a finished product but a separate material, so it needs to be assembled step by step. You can enjoy the fun of DIY at the mean time. 2、Gravity cart assembly toys are made of high quality wood, which is environmentally friendly, durable and safe, so that your children can enjoy the game time. 3、All the components in this toy set have been carefully processed and has no burrs to avoid scratching child's hand. 4、The kit can help children exercise their finger flexibility, problem-solving ability and hands-on ability during the assembly process. 5、Using the weight drop to drive the wheel rotation principle to build a cart, let the students simply understand the energy conservation. 1 x DIY Gravity Cart Kit Item Type:Gravity CartSize:15 x 8 x 31cm / 5.91 x 3.15 x 12.2in