Material: This drill bit holder is made of high quality carbon steel which make it practical. Wear-resistant, high-strength, not easy to damage Features: High quality connection rod, which has strong magnetic and anti-rust. The surface of screwdriver bit holder adopts phosphatized to prevent rust Magnetic Screwdriver Extension Bars: With the extra-strength magnet, this extension holder can hold bits securely Function: Screwdriver tools has good concentricity. Professionally designed for 1/4" hex shank bits. Package Include 10pcs screwdriver bit holder Widely Used: Screwdriver extension adapter is suitable for pneumatic screw drivers, electric drills, electric screwdrivers, screwdrivers, Manufacturer: Nikou