1.Material Steel Our adjustable spanners are made of high quality steel. The keys are not only corrosion and rust resistant, but also deformation resistant and shatterproof, which guarantees a long life 2.Special Design The wavy handle fits comfortably in the hand and is designed to be easy to handle. The distance between the two handles is adjustable, which reduces hand fatigue during use and allows compatibility with a range of grinder types 3. The wrench is designed for easy handling. Simply measure the diameter of the drill holes and choose a suitable specification. Then open the face hole wrench at a suitable angle and tighten the drill hole. Avoid applying too much force, otherwise the pen will break 4.Proper size: the total length of the wrench is approx. 161mm/6.34' You can choose between two sizes: the normal wrench and the introverted wrench. Regular wrench has 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, six models. And introverted wrench has 3 mm, 4 mm, 5 mm, three models