The video shows a close-up of a bicycle's rear derailleur and cassette. A person's hand is seen adjusting the derailleur, which is a device used to change gears on a bicycle. The cassette is made up of multiple sprockets of different sizes, and the derailleur is mounted on the frame of the bicycle. The person's hand is using a tool to make adjustments to the derailleur, possibly to ensure that it is functioning properly. The video is shot in a well-lit environment, and the focus is on the derailleur and cassette, with the background blurred.