Powered armor is a high-tech version of the suits of armor worn by medieval knights. Such suits commonly grant its wearer heightened strength and protection provided by an exoskeleton, internal life support for hostile environments, protection from environmental hazards such as radiation and vacuum, weapons systems (most often built into the suit's arms and torso), and some sort of transport mechanism that allows the wearer to fly, make giant leaps, or run at great speed along the ground.
A person wearing Powered Armor is naturally intimidating, and is capable of wreaking real havoc on a battlefield. In most depictions, the suit won't be much larger than an normal human being. Other types of Powered Armor are much larger, more like a bipedal vehicle the size of a tank or much larger (the latter is frequently called "Mecha" in Japanese anime). The usual distinction is that powered armor is generally form-fitting and is worn, while Mecha have cockpits and are driven.
Some suits of Powered Armor are life support units for their wearers who cannot remove their suits without dying.
Powered armor and battle-suits are a strongly developing technology. The armor used by Checkmate's rook agents are currently the state of the art in mass-produced battle armor, although individual inventors and major corporations have occasionally made one-of-a-kind models with significantly more power. Powered armors have been used in the world's military forces since 1991, when France deployed the first practical battle suits in the Gulf War. Despite this, due to their high cost and power consumption, powered armor is not widely deployed by any military outside of the United States. Since they require practice and skill to control (not to mention considerable support and upkeep), they are limited to elite units and special combat teams, and are rarely risked as point forces. Most of the time they are used for support, cover, and mop-up.
In yet another case of military technology finding civilian use, unarmored and unarmed powered suits (called "lifters") have been available to the construction and demolition trade for the last thirteen years. From the first slow, clumsy hydraulic rigs of 1995 to the near-man-sized exoskeletons of today, they have become an integral part of those industries. Some successful powered-armor superheroes have had suits that were clearly based around a commercially available civilian rig. For those who are curious, the typical model powered lifter is the John Deere Iron Man II model, which weighs 560 pounds and has a lifting capacity of 1 1/2 tons. It comes with headlamps, tool racks, and a built-in fire extinguisher as standard features. Manufacturers suggested retail price $75,000.