A hammer is a tool used to fasten, shape, or remove objects by striking them. It consists of a handle, also called a shaft, and a head, which is made of metal and attached to one end of the shaft. The head can be flat, round, or wedge-shaped and can have different sizes and weights to perform different tasks. Hammers are used in many different fields, such as construction, metalworking, crafts, carpentry, blacksmithing, and many other industries. There are also specialized hammers such as mason's hammers, locksmith's hammers, carpenter's hammers, splitting hammers and sledge hammers, each of which is optimized for specific tasks. Hammers can be hand operated or integrated into electric or pneumatic tools. It is important to pay attention to proper technique when using hammers to avoid injury.