External retaining rings are circular fasteners used to secure components on shafts or in housings. They fit into a groove on the outer diameter of a shaft, preventing parts from sliding off. These rings are commonly made from materials like stainless steel or carbon steel, providing durability and resistance to wear. These rings come in various sizes and styles, including snap rings and E-clips, to accommodate different applications. They are widely used in machinery, automotive, and aerospace industries, ensuring that parts remain in place during operation. Proper installation is crucial for their effectiveness and reliability.