4 years & up. Inspired by the world of construction, little engineers can put their building skills to the test with the Gears! Gears! Gears!® WreckerGears by Learning Resources. Build bulldozers, wrecking balls, or create your own designs. This open-ended building set allows children to engage in STEM experiences to develop early engineering and fine motor skills. Included: 47 colorful gear pieces and an activity guide.