This is a toy where you use various parts to design a course for a ball to roll through. It includes parts from two standard sets. The image shows the completed structure using all the parts. I haven't confirmed the exact number of parts, so please refer to the image. There are about 20 balls included. I've cleaned it as thoroughly as possible with alcohol wipes, but since it's a used item, please refrain from purchasing if you are concerned. *No returns accepted*