For optimal glow results, charge this product directly under the sunlight for 2-3 hours. The glow-in-the-dark feature will last longer if this product is not exposed to intense heat or direct sunlight for prolonged periods of time (longer than 3 hours). STEM & STEAM LEARNING - Early educational toys allow children to acquire a strong sense of architectural design, problem-solving skills, logic training, engineering knowledge, imagination, and brain development. REPLACES SCREEN TIME - Our creative and tactile toys promote less screen time and encourage actual play. Building blocks and learning toys help to reduce time spent with electronic devices such as TV, smartphones, and tablets. In The Box: Each glow-in-the-dark fort building kit connector comes with... x43 color vibrant geometric connectors & x82 reinforced connecting tube sticks.