The video shows a close-up of a bicycle's rear cassette and chain. A person's hand is seen adjusting the cassette, which has multiple sprockets of different sizes. The hand is using a tool to rotate the cassette, possibly to align it with the chain. The cassette is made of metal and has a shiny finish. The chain is silver and appears to be made of steel. The background is blurred, but it seems to be a workshop or garage setting.