Book of SecretsREADY TO BUILD UGears models are crafted from sustainably sourced, laser cut plywood sheets. Each Ready to Build kit contains everything you need inside the box, allowing you to start building right away. MECHANICAL Absolutely no need for batteries or electricityjust UGEARS. Each mechanical model is brought to life by the ingenious mechanisms crafted by your own hands. Simply wind up your model, and behold its enchanting motion as it springs to life.