The Mark I Armor was Tony Stark's first Iron Man suit, built to help him escape from forced captivity by the Ten Rings. The suit was crafted from the limited resources around him, including salvaged pieces of scrap metal and machine parts.
While in the captivity of the terrorist organisation, the Ten Rings, Tony Stark was forced to build one of his Jericho missiles for them. However, while working on the missile, Stark was secretly building an armoured suit to escape with the help of his fellow captive, Ho Yinsen.
Stark put the suit on and escaped the compound, but was forced to leave without Yinsen, who died of fatal gun shot wounds buying time for Stark to power up the armor. Once Stark exited the cave, he used the suit's flamethrowers to destroy the Ten Rings' stockpile of his own Stark Industries weapons.
While setting the camp ablaze the suit suffered damage from enemy gun fire, causing some of the suit's systems to malfunction or fail. With the suit nearing failure, Stark then used the suit's rudimentary rocket thrusters to escape the enemy camp just before the weapons detonated.
Stark managed to escape, but at the cost of the armor, which he was forced to leave behind. Once he returned to America, he used the suit's schematics to create a more advanced version of what he later referred to as the Iron Man suit.
The remains of the Mark I are later located in the desert by the remainder of the Ten Rings group, who retrieve its pieces and roughly reassemble it according to Stark's see-through schematics to examine its design. Later, during a secret meeting with the Ten Rings, Tony Stark's mentor and business partner, Obadiah Stane, stole the Mark I suit and used its design as the basis for his own Iron Monger Armor.
The armor greatly increased Stark's strength and durability, enabling him to overpower armed terrorists and survive an aerial impact with the ground after escaping. Multiple layers of durable metal salvaged from missile casings made the armor impervious to medium caliber firearms and reinforced its physical attacks.
The suit was powered by a small electric motor that is partially exposed at the suit's lower back. The engine powered a pair of external, belt driven mechanisms in the suit's legs that helped support the vast weight of the metal suit. Similar mechanisms in the suit's arms and legs helped Stark to move around while wearing the armor and amplified the strength behind his movements, allowing him to throw punches that could destroy a heavy metal door, knock human enemies back several feet, and partially embedded his arm in a cave wall.
The armor's only weapons were a pair of flamethrowers mounted on each arm along with one single-shot missile concealed in the left arm. While not capable of sustained flight, the armor was capable of limited flight through single-fire rocket thrusters located on the back of each leg, enabling him to escape during the destruction of the Ten Rings' camp.