Manufactured from SNCM-V steel hardened and tempered with shot blasted finish. 1/2" square drive holder made from chrome vanadium steel hardened, tempered and chrome plated for corrosion resistance. there are six hexagonal bits in this pack 4, 5, 6, 8, 10 and 12 mm that are all 30 mm long and a 1/2" drive socket bit.