Individual Screw Chuck Screwdrivers Well-constructed, precision screwdrivers with replaceable blades that are held firmly in the handle by means of screw chucks. Blades are made of quality tool steel, which have been heat treated for toughness and long wear. The bodies are plated and have hexagonal swivel heads which will not roll on bench. 3-1/2" (89mm) overall length. Supplied in packages of 3 screwdrivers. Available in 6 sizes.