3X Marine Ruler Parallel Ruler Nautical Charts Parallel Ruler Mapping Points to Pull Parallel Ruler 450MM

3X Marine Ruler Parallel Ruler Nautical Charts Parallel Ruler Mapping Points to Pull Parallel Ruler 450MM The main role: Before Chartwork for drawing lines bearing line or course, the degree or amount of bearing line degree course line. Two hands each holding a ruler of David, alternately moved in parallel. Usage: When the move operation, the appropriate force to suppress static hand -foot, one hand pushing moving feet, two feet alternately moved in parallel until the required position. Alternately moving, to prevent the static foot displacement. colour:Transparent color Material:plastic size:450mm Package Contents: 3*Chart parallel ruler Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.