HIGH QUALITYPlastic material, wear resistance, not easy to deform, and will not scratch your hands. LARGE NUMBERSClear large numbers design measurement easy to read, suitable for blackboard, whiteboard, dry erase board, etc. EASY TO USEHollow center design, with detachable handle the teaching ruler is easy to grip. Size Chart90 Degree Ruler: 66x57x33cm or 25.98x22.44x12.99inch 45 Degree Ruler: 56x40cm or 22.05x15.75inch Protractor: 50cm or 19.69inch Compass: 43x41cm or 16.93x16.14inch. You can choose 1 or 2 or 4pcs rulers as your needs. WIDE APPLICATIONMath geometry tool kit are essential tools for architects, engineers, artists, designers, teachers and so on. Appropriate big size to use for geometry drawing and math class, fits for classroom, school or office. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store