In the video, we see a close-up of a person's hand holding a metal tool and using it to adjust the tension on a bicycle's chain. The tool is inserted into the chain and turned, causing the chain to move along the gears. The person's hand is steady, and they appear to be experienced in using the tool. The gears are silver and have a metallic sheen, and the chain is also silver. The background is blurred, but it appears to be a workshop or garage setting.