The sand timer, more commonly referred to as the hourglass, is a device used to keep track of time. Minutes are measured as sand moves from bulb to bulb. During a voyage, the hour glass would be one of few reliable ways to measure time at sea alongside a compass to assist overall navigation. This brass, invertible hourglass stands on a metal base, navigating us through our days. Made out of brass with a two-tone antique finish. Revolving sand timer. The sand flow duration is approximately 2 minute and 45 seconds.