beautifully designed kit to help children understand mechanical structures and transmission principles. Non-toxic, smooth, burr-free, and durable. Readily assembleable; other accessories are easy to assemble, developing children's hands-on skills. Ideal for parent-child interaction or intellectual development, stimulating children's learning enjoyment. Can develop children's hands-on skills and other abilities. Cultivates children's curiosity and exploration of science in a very fun way. Specifications: Material: Wood Size Chart: 7cm x 14cm x 8cm / 2.76 inches x 5.51 inches x 3.15 inches Package Includes: 1 DIY Science Experiment Kit Note: 1. This is not a baby toy; keep out of reach of children to avoid accidental ingestion. 2. Due to manual measurement and differences in monitors, please refer to the actual product.