The Invicta men's Subaqua Noma III Collection 7750 automatic watch is sure to satisfy your every time-telling need with a sophisticated flair. The 50-millimeter case is constructed out of 23-karat-rose-gold-plated stainless steel, with a black stainless steel bezel, and a matching 23-karat-rose-gold-plated stainless steel textured band that includes a fold-over clasp with safety mechanism for a perfectly secure fit. The dial window is made of tough, scratch-resistant sapphire and protects the black dial face, which features rose-gold hour indexes, three eye-catching chronograph sub-dials, and a handy date-and-day calendar at three o'clock. In addition, a gray tachymeter circles the dial face, and large white Arabic numerals line the unidirectional bezel at five-minute intervals. Powered by automatic movement, this stylish timepiece is water resistant to 1640 feet.Subaqua CollectionLed with expert engineering, and always ready to face the depths, no feat or occasion will ever be too great for Invicta’s Subaqua to handle. The sheer magnitude of this mighty timepiece is superbly executed with surgical-grade solid stainless steel, Swiss automatic movements, and multiple color options of ionic plating. Managing up to 500 meters of water, finished off with a unidirectional rotating bezel, integrated shock resistance, and Invicta’s luminous Tritnite hands, the Subaqua is the diver’s definitive in negotiating any adventure by sea or by land.Screw Down Crowns: Many Invicta watches are equipped with a screw down crown to help prevent water infiltration. This is most common on our Diver models. In order to adjust the date and/or time on such a watch, you must first unscrew the crown before you can gently pull it out to its first or second click stop position. To do this, simply rotate the crown counterclockwise until it springs open. When you have finished setting the watch, the crown must then be pushed in and screwed back in tightly. Not doing so will cancel the water resistance of the watch and will void all warranties from the manufacturer. Overall, this process should not require a lot of effort or force.Automatic WatchesAutomatic watches do not operate on batteries. Automatic watches are made up of about 130 or more parts that work together to tell time. Automatic movements mark the passage of time by a series of gear mechanisms, and are wound by the movement of your wrist as you wear it. The gear train then transmits the power to the escapement, which distributes the impulses, turning the balance wheel. The balance wheel is the time regulating organ of a mechanical watch, which vibrates on a spiral hairspring. Lengthening or shortening the balance spring makes the balance wheel go faster or slower to advance or retard the watch. The travel of the balance wheel from one extreme to the other and back again is called oscillation. Lastly, automatic movements come in different types, including movements that are Swiss-made, Japanese-made, and more.Also referred to as self-winding, watches with automatic movements utilize kinetic energy, the swinging of your arm, to provide energy to an oscillating rotor to keep the watch ticking. They're considered more satisfying to watch collectors (horologists) because of the engineering artistry that goes into the hundreds of parts that make up the movement. If you do not wear an automatic watch consistently (for about 8 to 12 hours a day), you can keep the watch powered with a watch winder (a great gift for collectors).