【High Quality Formwork Drill Bit】 - Made of chrome vanadium steel (CR-V), these bit holders are highly resistant to abrasion and extreme hardness for long life. 【Perfect Connection & Stable】 - 3 different lengths: 60mm, 100mm, 150mm, adapt perfectly to your work tools. This allows you to extend any type of screwdriver and use the screwdriver head conversion. 【Easy assembly and strong magnetism】 - Magnetic screwdriver bit holder has a must-have locking mechanism in interfaces, with built-in strong magnet and automatic collector for quick attachment in home and business. 【Universal & Convenient】 - This bit holder set is a great tooling accessory for conversion, suitable for 1/4 universal hex drills and drill bits. 【Application】 - Suitable for DIY, profession, repair and more. A must for renovation and leisure! Cordless Screwdriver Extension - Chrome Vanadium Chromium vanadium is particularly stable and hard, used for the production of high quality tools. No sharp edges, suitable for