K'nex STEM Explorations - Levers and Pulleys - 8yrs+See science concepts in action with the K'NEX Education STEM Explorations Levers and Pulleys Building Set! K'NEX STEM Explorations Levers and Pulleys Set contains 139 pieces that students can use to build three replicas of real world simple machines. K'NEX kits don't just keep kids occupied, they also foster their imaginations in creating designs. Using the downloadable activities, teachers can guide children in learning about lever classes, pulley