This is the 660-piece set designed in Germany that introduces young engineers to the functions of pneumatics and the use of compressed air as they build six different models. The set includes compressors, pneumatic valves and cylinders, and an exhaust throttle valve that demonstrate how compressed air can power components of a realistic tractor with tree grabber, front loader, double swather, and more. The set also bolsters a child’s motor skills as it reinforces STEM concepts. Includes step-by-step manual. Requires 9-volt battery. Ages 9 and up. Box 18 1/4" L x 9" W x 3 1/4" D. (4 lbs.)