Sharpeners are tools designed to refine the edges of blades, pencils, or other pointed objects. They work by removing material from the surface to create a sharper point or edge, enhancing performance and precision. Common types include manual sharpeners, electric sharpeners, and whetstones, each suited for different applications. In the context of writing, pencil sharpeners are often used in schools and offices to maintain the sharpness of pencils. For knives and other cutting tools, whetstones and electric sharpeners are popular choices, providing a more refined edge for better cutting efficiency.