A ball peen hammer is a type of hand tool commonly used in metalworking and mechanical tasks. It features a flat striking surface on one end and a rounded, ball-shaped end on the other. The flat side is used for driving nails and shaping metal, while the rounded end is ideal for peening, which is the process of shaping or compressing metal surfaces. These hammers are typically made of steel and come in various sizes, making them versatile for different applications. They are essential tools for blacksmiths, machinists, and anyone working with metal, as they help create precise shapes and finishes.