660pcs Crossbow Puzzle Toys Intelligence Hand Assembly Mechanical Gear Transmission Building Blocks High Difficulty Metal Model

1. Alloy material, mechanical device, anti-collision and drop-resistant
2. Can be used as home furnishings after assembly
3. DIY assembly, stimulate logical thinking, improve children's hands and brain ability
4. Parent-child interaction, exercise hands-on ability
5. Physical construction model, difficult to assemble by hand.
6. Smooth edges do not hurt your hands
7. Material: stainless steel