This compass has permanent compensation for magnetic declination and a clinometer for inclined angles. Magnifying mirror and sighting hole at the lower edge of the mirror for the most accurate bearings. Silicon rubber feet for best friction on map when taking bearings. Romer scales of 1:50.000 and 1:25.000 for plotting positions on maps and mm/inch map measuring scales. Built-in magnifying lens and luminous markings for night navigation are other important features for the most demanding users. As recommended by Ray Mears.