Iron sights are the simple, inexpensive, and standard sighting system found on most handguns. These mechanical sights typically consist of a front sight post or blade near the muzzle and a rear sight with a notch or aperture at the back of the slide or frame.
To use iron sights properly, the shooter aligns the front sight within the rear sight notch (often called "sight picture") and then aligns both with the target. Common alignment methods include the "equal height, equal light" principle where the tops of both sights are level with equal spacing on either side of the front sight.
Iron sights require no batteries, have no electronics to fail, and can withstand harsh conditions, making them extremely reliable. While they lack the rapid target acquisition of red dot sights or the magnification of scopes, they remain the standard aiming system for most production handguns due to their simplicity, durability, and low cost.