A rear shock is a component found in many types of vehicles, including bicycles and motorcycles, designed to absorb bumps and impacts from the road or terrain. It helps maintain stability and comfort by allowing the rear wheel to move up and down independently, improving traction and control. In bicycles, rear shocks are often part of a suspension system that enhances performance on rough trails. They come in various types, such as coil and air shocks, each offering different levels of adjustability and responsiveness to suit different riding styles and conditions.