These plastic rulers are clear and a great school essential to have. These are durable and will last for years to come. The clear ruler makes it easier to see the document or item you are measuring for clear and concise measurements. Also, for drawing straight lines in all art works. A ruler can be used in geometry, for technical drawing, helping with printing, engineering and building to measure distances or to rule straight lines. The ruler has a straight edge which may also contain calibrated lines to measure distances. Pack of 30 clear plastic rulers measuring 0 – 30cm on one edge and 0 – 12 inches on the other for all measuring needs.