Made of chrome vanadium steel with long life and durability in use. Solid inner hex socket without magnet. This set of screwdriver bits will fit most corded or cordless drills for hex head screws. 9 hex sockets: 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm. Many applications. Suitable for household DIY, woodworking, auto parts, professional machine repair, etc. This is a set of durable 4 piece reduction and boost adapters. Heavy-duty chrome vanadium steel construction is designed for use with ratchet wrenches. A black oxide finish makes each part corrosion resistant and very durable. Spring loaded ball stop keeps your bushings fixed and secure. There is a range of sizes to fit many socket or wrench combinations including 1/2 (M) - 3/8 (F), 3/8 (M) - 1 / 4 (F), 3/8 (M) - 1/2 (F) and 1/4 (M) - 3/8 (F). Specifications: -Material: chrome vanadium steel -Surface finish: electroplating, blackening -Hardness: 45 ± 2 (HRC) -Color: black -Size: 1/2 (male) - 3/8 (female) 3/8 (male) - 1/4