Crafted from shatterproof, these clear triangular scale rulers combine light weight portability with enhanced compared to glass / metal alternatives, maintaining structural integrity even with frequent classroom use The waterpoof construction ensures safe daily handling while supporting learning environment, with beveled edges smudges on technical drafting and engineering drawing Perfect for classroom geometry teaching demonstrations, architectural sketching practice, and science drafting project Suitable for school students and educators requiring multifunctional measurement tool for geometry classes, physics experiments, and math exam preparation This clear triangular ruler set ( 15cm & 20cm) delivers precisely measurement with its geometry triangular designs, featuring clear acrylic construction that eliminates visual obstructions during technical drawing and geometry drafting tasks, Manufacturer: KAHDGSS