Screwdriver bits are interchangeable, detachable tips that fit into drivers (handheld or power drills) to turn various screws, coming in common types like Phillips (+), Slotted/Flathead (-), Hex (6-sided), and Torx (star-shaped), plus specialty shapes like Pozidriv (PZ) or Square (Robertson). Sets offer many sizes (e.g., #1, #2 Phillips; T25 Torx) for diverse tasks, from electronics to construction, with options for impact drivers (impact-ready) or standard drills.