In the video, a person is seen holding a black gear in their hands. The gear has a ribbed surface and a hole in the center. The person then places a smaller gear with a similar design onto the larger gear. The smaller gear has a circular shape with a series of holes around the edge. The person then rotates the smaller gear, demonstrating how it fits onto the larger gear. The video focuses on the interaction between the two gears, highlighting their design and how they fit together.