Weems & Plath 24 Parallel Ruler
$45
These are the best 24 Rulers for the money! Used to plot a course from a convenient meridian, parallel or compass rose on a chart. Weems & Plath Rulers are of superior craftsmanship and quality. The see-through lines and scale on the Rulers make plotting courses much easier. Simply place the lines inside the Weems & Plath Ruler directly over the positions on your chart and you have a flawless plotting advantage. Lifetime Warranty.