HIGH QUALITY CARBON STEEL: The screwdriver bit holder is made of high quality carbon steel + CRV, which has high hardness, non-slip, large torque and durable. You can use them for a long time. EXTENSION TOOLS: The screwdriver bit holder is 1/4 inch Hex extensions are a must-have accessory set for electric drills and screwdrivers. percussion, ideal for extending all kinds of screwdriver bits, drills, batch heads, screwdriver head conversion uses. MAGNETIC DESIGN: The built-in magnetic quick release and magnetic bit holder extension rod will greatly improve work efficiency, allowing you to complete your work more easily and quickly. It can be a great choice for daily repair or installation work. WIDE APPLICATION: The quick release magnetic bit holder is suitable for electric screwdrivers and is used in engineering, machinery, home appliance maintenance and other production lines.Ideal for working on vehicles, bicycles and furniture, etc. HIGH VALUE PACKAGE: You will get 9 pieces