Both sides are clearly marked, which ensures comfort and accuracy Rulers are perfect for use in schools, offices and Suitable for carpenters, engineers and architects, for drawing straight This stainless steel ruler contains 3 rulers in different sizes: 15cm ( 5.91in), 20cm ( 7.87in), 30cm ( 11.81in Perfect for architects, engineers, students, and enthusiasts requiring measurement tools for technical drawings or school projects, Manufacturer: ERRORY