T - 45d power armor The T - 45d power armor is a piece of armor found in " Fallout 3 " , " " , " Fallout Shelter " and " Fallout 4 " . Background . < section begin = " background " / > Originally developed and manufactured for the United States Army by American defense contractor West Tek , the T - 45d power armor was the first version of power armor to be successfully deployed in battle . In 2067 , the first suit of T - 45d power armor was deployed in Alaska during the start of the Anchorage Reclamation in the midst of the Sino - American War . This power armor was incredibly effective against Chinese tanks and infantry . Its ability to allow a single infantryman to carry heavy ordnance that otherwise required a team of soldiers to transport and operate became key in various localized conflicts on the Alaskan front , and it allowed American soldiers wearing the armor to destroy entire towns occupied by Chinese troops without endangering themselves . In 2076 , the more advanced T - 51b power armor variant was introduced into combat duty . After the Great War , this model of power armor is still being used by factions such as the Brotherhood of Steel . While main forces of the Brotherhood in New California and the Mojave Brotherhood of Steel tend to use the newer T - 51b , more remote chapters , such as the East Coast Brotherhood of Steel and the Brotherhood Outcasts , have to rely on these outdated suits . < section end = " background " / > Design . < section begin = " design " / > The T - 45d lacks the mobility of later power armor models ( such as the T - 51b power armor ) because of its less advanced servo design ; as a result it limits the wearer ' s Agility . The first version of T - 45d power armor deployed on the front lines against the Chinese was powered by small energy cell s and it burned through them at an alarming rate . While the T - 45d armor is similar in its overall shape to the newer T - 51b power armor , it is significantly less advanced than its later counterpart , and uses riveted steel plates instead of plastic composite materials in its construction . Various electronic and mechanical subsystems of the armor are exposed on the outside of its casing rather than sealed within as in the T - 51b , making it far more susceptible to damage . In addition , a specialized body suit is required to be worn underneath the T - 45d ' s armored shell in order to facilitate linking the armor ' s servos to the wearer ' s own motions and to make the armor more bearable because of its heat dissipation problems . < section end = " design " / > Variants . T - 45d power armor . T - 45d suits were used by the Brotherhood of Steel , especially used by Brotherhood Knights and Paladins , along with modifications and makeshift repairs . Other variations can be found in terms of coloring and other decorations . MP - 47 / A prototype medic power armor . The MP - 47 / A prototype medic power armor is a U . S . Army variant of T - 45d power armor . It was designed to administer medical attention to the user as necessary during combat . The prototype medic power armor has the ability to administer Med - X , which it will do if the wearer ' s health drops below 33 % , if a limb ' s health drops below 25 % , or if both of these conditions are met Med - X will be dispensed every 2 . 5 hours . Unlike standard Med - X injections , this process carries no risk of addiction . However , it does draw from the wearer ' s supply of Med - X , and thus the feature is useless if the player has none . As noted in the accompanying manual , the prototype version of the suit lacks the ability to dispense anything other than Med - X , whereas the completed version would have had a wider range of features , such as deploying stimpaks . The armor was planned as an automatic medical supply dispenser , meaning troops would not have to be evacuated for medical treatment . The user manual found with the armor details that the final version was to also include a lethal chemical that would trigger if the soldier deserted .