[(firm clamping)] : unique design drill chuck can easily convert the torque applied by the handle into a larger clamping force, hold the drill bit firmly and solidly, not easy to loosen. wide range of tightening: keyless chuck, clamping range: 2 ~ 13 mm/0.04 ~ 0.51 inches, connection size 1/2-20unf, diameter: 43 mm/1.69 inches, length: 58 mm/2.28 inches, it is suitable for many types of drills. [(reasonable design)] this is a keyless self-tightening drill chuck; the keyless and self-tightening type design is more in line with human engineering. [(easy to use)] : quick change self-tightening drill chuck is easy to install and disassemble, saves effort and more convenient, no complex operation required. [(quality assurance)] made under strict quality control standards, it must undergo many quality and safety inspections before leaving the factory to ensure quality and stability.