Many people can't get both sides of a pair of binoculars to focus, or find them too heavy to hold up to their eyes for any length of time. A monocular may be the answer. For a given magnification they are lighter and easier to hold steady, and simpler to use because there is only one set of controls. Many sailors also appreciate the fact that they can use their other (now spare) hand to hold on to the ship! 10x magnification through a 25mm object lens. Tough rubberised casing and supplied with a leatherette belt pouch. 4.5" long. Great gift for the explorer in all of us!