The Office ruler is made of aluminum alloy, the surface is anodic oxidation to prevent rust and corrosion and is not easy to break. It is durable and sturdy, has a shatterproof design for long lasting use.The children's ruler has smooth edges, and the four corners are rounded, so don't have to worry about hurting your hands. The ruler has a metric scale on one side and an English scale on the other for convenient measurement. In addition, it comes with a small hole that can be used to hang for easy storage without taking up space.The small ruler is perfect for children and is a useful measuring tool in learning, it can be used in math classrooms, teacher teaching, class, office, home, etc.Please do not store the ruler with metal or sharp objects, so as to avoid scratches on the ruler, which may cause inaccurate scales.