1.25" without back paper, likely as it was issued. Tiniest age traces on the reverse with front displaying glossy and NM. Depicted is northern hemisphere of the world globe with illustration of full figure man planting American flag at the pole while to the left is a tiny image of supply loaded dog sled with two men nearby. Full inscription is "Cook's Compass/North Pole/Discovered April 21, 1908/Clock Shows Exact Time Flag Was Planted." We do not know what the text referencing a "Clock" refers to as there is no indication of hours as part of the button's design but in any case this is the only button we know of documenting Cook's claim of reaching the pole in 1908, a claim which was very shortly hotly disputed. Rare.