The video shows a close-up of a bicycle's rear derailleur, which is the mechanism that moves the chain across the gears. The derailleur is made by Shimano and is attached to a red bicycle frame. The chain is visible and appears to be in motion, indicating that the bicycle is being ridden. The background is a concrete sidewalk with some grass visible in the bottom right corner. The video does not show the rider or any other part of the bicycle.