4 years & up. Straws and Connectors are ideal in helping children develop Science, Technology, Engineering®, and Math (STEM) skills. It allows children to enhance hand-eye coordination, motor skills, logic, and problem-solving skills all while playing. Build a fort, rocket, boat, tower, tunnel, or bridge! Design your own scientific model, or create something unique. The opportunities are endless! The straws fit snugly on the connectors and are flexible so you can build arches and tubes. This set includes 400 pieces (232 straws and 168 connectors).