Vast Assortment for Different Use: this drill extension bit holder set includes 8 pieces of bit driver extension holders and 8 bits; It features 4 different sizes (about 12 inch/ 300 mm, 2.5 inch/ 65 mm, 4 inch/ 100 mm and 6 inch/ 150 mm) with 2 pieces for each size offering a broad selection for tasks; No matter what your daily use or replacement needs are, our set has got you covered Ideal Drill Bit Extender: the 1/4 inch driver adapter and 1/4 inch hex shank an ideal fit for the bits; You can rest of firm and secure drilling and driving, improving the overall efficiency and safety of your work process Material: every drill bit extension set in this set is made from steel; This construction makes them stable and strong, capable of withstanding high pressure, and resistant to problems from contact with oils or other fluids Practical Magnetic Design: the bottom hole part of the hex bit extension is magnetized, ensuring that the screwdriver bits stay steady and firmly fixed on screws;