PS Armor the most distinctive feature of the prototype Gundams developed by the Atlantic Federation. While active, this special armor nullifies all attacks by physical weapons, including blades, projectiles, and conventional explosives. However, it has no effect against beam and laser weapons, so most of the Gundams also carry shields treated with anti-beam coating. And because PS Armor consumes large amounts of energy, it cannot be used for extended periods lest it drain the mobile suit's energy battery.
PS Armor changes color upon activation. The Gundams which use this technology thus sport brilliant colors while in their Active Mode, and turn a dull gray when they switch to Deactive Mode.