1Description of Function: The parallel ruler is used for drawing azimuth lines or navigation lines and measuring azimuth line degrees or heading line degrees when chart operations are carried out. 2High Transparency: Our navigation parallel ruler has high transparency, clear scale and accurate measurement, so that you can have a nice experience of using it. 3Copper and Acrylic Material: Our parallel ruler is made of copper and acrylic material, the pure copper spacer is polished, not easy to oxidize and with stable face. 4Flexible Operation: This navigation parallel ruler is very easy and flexible to operate, just follow the actual needs and routine operation. 5Exquisite Craftsmanship: This marine navigation parallel ruler is light in weight, easy to carry, and exquisite craftsmanship, so you can achieve stable use.