These bit extension holders are made with high quality stainless steel and chromium-vanadium steel with heavy duty construction to ensure maximum durability. It can be used for a variety of electric screwdrivers and bits making this extension holder very handy and multipurpose. Features: Hard steel holder for maximum durability, the heavy-duty construction allows for long service life. Bit holders have strong magnetoconductivity for quick connect or disconnect and ensuring stay in place while driving. Universal 1/4inch quick hex shank and 1/4inch hex socket fit most electric screwdrivers and bits. The small size allows you to bring your bit extension anywhere to get any job done and can fit into many tool bag. There are three extension holders in different lengths and you can use the proper one for various needs. Specifications: Color: Red, Yellow(Optional) Material: Stainless steel and chromium-vanadium steel Hex Shank Size: 6.35mm(1/4") Hex Socket Size: 6.35mm(1/4") Length: 60mm(2.36"), 100mm(3.93"), 150mm(5.9") Quantity: 3 Package Includes: 3 x Bit Holders