Description:These extension holders are made with a high quality metal with heavy duty construction to ensure durability and efficiency. They are covered with anti-proof cover and the cover is separated from holder body so you can hold cover while using electric screwdrivers, in order to avoid waggle. They can be used for a variety of drivers making these extension holders very handy.Features:Hard metal holder for durability, the heavy-duty construction allows for long service life. Bit holders are designed to be extendable and can be lengthenedwith a simple pull. 1 or 4inch quick hex shank and 1 or 4inch hex socket fit most electric drivers, hand-held drivers 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. Very helpful to remove or tighten a large number of screws after you've started or loosened them.Specifications:Main Material: 08F iron, aluminumHex Shank: 1 or 4"Hex Socket: 1 or 4"Retracted Length: 80mm(3.15"), 120mm(4.72")Extended Length: 120mm(4.72"), 200mm(7.87")Quantity: 2Package Includes:2 x Extension Holder