A roller chain is a mechanical transmission device commonly used to transmit power and motion in various industrial applications. It consists of a series of connected cylindrical rollers linked together by inner and outer plates. These chains are designed to engage with sprockets or gears, allowing for efficient power transfer and motion. Roller chains are used in a wide range of machinery, such as motorcycles, bicycles, conveyors, and manufacturing equipment. They are valued for their strength, durability, and ability to transmit high loads, making them a vital component in many mechanical systems. Proper lubrication and maintenance are essential for their longevity and performance.