Stainless steel case. Fixed stainless steel bezel. Black dial with silver-tone hands. Automatic movement. Scratch resistant sapphire crystal. Solid case back. Case diameter: 39 mm. Round case shape. Casual watch style. The Panerai Nautical Curvimeter is an instrument used to measure distances on a nautical chart. The measurement is carried out by tracing the route with a small wheel, the rotation of which is conveyed through a series of gears to a hand which indicates on the dial how many nautical miles have been covered. The graduated circles on the dial correspond to the scale of the chart being used. Panerai Curvimeter Black Dial PAM00302.