Premium forged steel alloy - Construction: 4 precision files made from T12 drop-forged alloy steel; 12 needle files made from GCR15 bearing steel. High-temperature surface quenching increases hardness and wear resistance for longer life. - 17-piece value set: includes 4 engineer files of 20.3 cm in flat, half-round, and round shapes; 12 precision needle files of 10.7 cm in square, round, cone, equaling, ring, warding, and triangular shapes; plus 1 multifunction brush for cleaning and maintaining bits and files made for metal, wood, plastic, glass, ceramic and leather. - Comfort and control: soft rubber handles provide a secure grip on each file, enabling longer work with reduced fatigue. - Portable storage: comes with a tool bag to organize and protect both mini and larger files; a top strap makes carrying easier and more convenient. - Use scenarios: - Deburring, smoothing, and fine finishing of metal parts, brackets, and prototypes. - Detailing and shaping in wood, plastic, glass, ceramic, and leather projects. - Precise internal corners, radii, and fitting work with the needle files for delicate adjustments.