A putty knife is a flat, flexible tool used primarily for applying and smoothing materials like putty or spackle. It typically has a metal blade and a comfortable handle, making it easy to maneuver in tight spaces. Putty knives come in various sizes, allowing users to choose the right one for their specific tasks. In addition to applying putty, a putty knife can also be used for scraping surfaces, removing paint, or cleaning up excess materials. Its versatility makes it a common tool in home improvement and construction projects, as well as for crafting and repair work.