Screwdrivers are tools, manual or powered, used for turning screws. They have a handle and a shaft, ending in a tip that fits into the head of a screw. Screwdrivers come in different types and sizes, depending on the shape and size of the screw head. Some common types are slotted, Phillips, Torx, hex, and Robertson. Screwdrivers are used for various purposes, such as assembling furniture, repairing appliances, installing hardware, etc. Powered screwdrivers are faster and easier to use than manual ones, and can also drill holes. Some powered screwdrivers have features such as variable speed, reversible direction, torque clutch, etc.