3 - 7 years. This K'Nex set is ideal for children with varying manipulative skills. Build 8 models with corresponding cards or create your own one-of-a-kind creature using the 131 piece set. This set includes 10 vibrant and hypnotic eyes, as well as a pair of ears that can also be used as wings. Each group building set can accommodate 6 to 8 children. Clean up is easy with this handy, reusable container with lid. Building with K'NEX® puts children on a path towards a fundamental understanding of STEAM/STEM subjects.