Iron Man possesses powered armor that gives him superhuman strength and durability, flight, and an array of weapons. The armor is invented and worn by Stark (with occasional short-term exceptions). Other people who have assumed the Iron Man identity include Stark's long-time partner and best friend James Rhodes; close associates Harold "Happy" Hogan; Eddie March; and (briefly) Michael O'Brien.
The weapons systems of the suit have changed over the years, but Iron Man's standard offensive weapons have always been the repulsor rays that are fired from the palms of his gauntlets. Other weapons built into various incarnations of the armor include: the uni-beam projector in its chest; pulse bolts (that pick up kinetic energy along the way; so the farther they travel, the harder they hit); an electromagnetic pulse generator; and a defensive energy shield that can be extended up to 360 degrees. Other capabilities include: generating ultra-freon (i.e., a freeze-beam); creating and manipulating magnetic fields; emitting sonic blasts; and projecting 3-dimensional holograms (to create decoys).
In addition to the general-purpose model he wears, Stark has developed several specialized suits for space travel, deep-sea diving, stealth, and other special purposes. Stark has modified suits, like the Hulkbuster heavy armor. The Hulkbuster armor is composed of add-ons to his so-called modular armor, designed to enhance its strength and durability enough to engage the Incredible Hulk in a fight. A later model, designed for use against Thor, is modeled on the Destroyer and uses a mystical power source. Stark develops an electronics pack during the Armor Wars that, when attached to armors that use Stark technologies, will burn out those components, rendering the suit useless. This pack is ineffective on later models. While it is typically associated with James Rhodes, the War-Machine armor began as one of Stark's specialty armors.
The most recent models of Stark's armor, beginning with the Extremis Armor, are now stored in the hollow portions of Stark's bones, and the personal area networking implement used to control it is implanted in his forearm, and connected directly to his central nervous system.
The Extremis has since been removed, and he now uses more conventional armors. Some armors still take a liquid form, but are not stored within his body. His Endo-Sym Armor incorporates a combination of the liquid smart-metal with the alien Venom symbiote, psionically controlled by Stark.
Post-Secret Wars, Stark uses a more streamlined suit of armor that can practically 'morph' into other armors or weapons.
After being critically injured during a battle with the Extremis-enhanced Mallen, Stark injects his nervous system with modified techno-organic virus-like body restructuring machines (the Extremis process). By rewriting his own biology, Stark is able to save his life, gain an enhanced healing factor, and partially merge with the Iron Man armor, superseding the need for bulky, AI-controlled armors in favor of lighter designs, technopathically controlled by his own brain. His enhanced technopathy extends to every piece of technology, limitless and effortlessly due to his ability to interface with communication satellites and wireless connections to increase his "range". Some components of the armor-sheath are now stored in Tony's body, able to be recalled, and extruded from his own skin, at will.
During the "Secret Invasion" storyline the Extremis package is catastrophically shut down by a virus, forcing him again to rely on the previous iteration of his armor, and restoring his previous limitations. Furthermore, Osborn's takeover of most of the few remaining Starktech factories, with Ezekiel Stane systematically crippling the others, limits Tony to the use of lesser, older and weaker armors.
After being forced to "wipe out" his brain to prevent Norman Osborn from gaining his information, Tony Stark is forced to have a new arc reactor, of Rand design installed in his chest. The process greatly improves his strength, stamina and intellect. The procedure left him with virtually no autonomic functions: as his brain was stripped of every biological function, Tony is forced to rely on a digital backup of his memories (leaving him with severe gaps and lapses in his long-term memory) and on software routine in the arc reactor for basic stimuli reaction, such as blinking and breathing. The Bleeding Edge package of armor and physical enhancement is now equal in power, if not a more advanced, version of the old Extremis tech.