In the video, a person is seen holding a bicycle's rear derailleur with their left hand while using their right hand to rotate the crankset. The derailleur is silver and black, and the crankset is also silver. The person is wearing a black jacket and blue jeans. The background is blurred, but it appears to be an outdoor setting with trees and a clear sky. The person is rotating the crankset in a clockwise direction, and the derailleur is moving up and down in response to the rotation.