... (hardness) 2, good quality 3, professional Insert screwdriver bit setManufacture and supply various full series of screwdriver bits, nutsetters, nut drivers, sockets, socket ... -coating, Cr-coating, Zn-coatingHead types:PH, PZ, slot, Torx, square, hex, hex-plus, Z-spanner, Torx hollow, Torx plus, tri ...