Comprehensive groups: comes with 20 pieces plastic rulers totally in clear Material: these straight rulers are made of elastic and durable plastic, safe and no incisive edges, friendly to hands and skins, hard to scratch your hand, suitable for students and adults 2-in-1 Design: these office rulers are designed with both metric and inches, the ranges of the measurement length are 0-30 cm and 0-12 inches, reasonable sizes are suitable for most uses Wide applications: great for schoolwork or activities that require straight lines, and artists, designers, architects, engineers, students; Suitable for classroom, school, office, home and more usages A nice gift: a great choice to share with teachers and students as a gift, easy to read the scale clearly, and can be accurately measured, won’t easily fade, keep the colors and looks for a long time.