3 - 7 years. Make 6 transportation models at once with these 183 pieces! Create models out of big, soft, chunky K'nex pieces that are easy to assemble, stay together during play, and can be quickly dismantled for easy clean up. Great for children with varying fine motor skills. Building with K?NEX puts children on a path towards a fundamental understanding of STEAM/STEM subjects. K?NEX supports key areas of a child's developmental growth. As they click the different parts together and discover how the building system works, they?re strengthening hand-eye coordination, fine motor skills, problem-solving skills, spatial awareness and exercising their imagination! Each set includes building cards and storage tub with snap-on lid.