T - 51b power armor < section begin = " CXGamesSummary " / > T - 51b powered infantry armor , or power armor , represented the peak of armored infantry technology before the Great War , surpassed only by its successor , the T - 60 power armor . Developed in the laboratories of the West Tek Research Facility , the T - 51b was deployed at the end of the Anchorage Reclamation , and by January 2077 , the armor had become standard issue for American soldier s in the Army ' s Mechanized Cavalry Regiments . Now , only the most technologically advanced factions with ties to the pre - Great War American military or federal government , such as the Brotherhood of Steel or the Enclave , have access to this type of power armor . < section end = " CXGamesSummary " / > Design . The armor is fitted with a back - mounted TX - 28 MicroFusion Pack which generates an output power of 60 , 000 Watts to power the HiFlo hydraulic systems built into the frame of the suit . Made of a poly - laminate composite , the outer shell of the T - 51b is lightweight and capable of absorbing over 2500 Joules of kinetic impact . The 10 - micron - thick silver ablative coating can reflect laser and other radiation emissions without damaging the composite subsurface , and the eyeslit for the helmet is made of bullet proof glass to protect the wearer from any projectiles . Post - War use . The Brotherhood of Steel does not possess the technology required to manufacture new suits of power armor and relies only on repaired and refurbished pre - Great War suits . Among the soldiers of the Enclave , this power armor is seen as obsolete , as it was replaced by the Enclave ' s advanced power armor and advanced power armor Mk II models , though it is still used by soldiers of the Enclave who have not been issued the newer armor . As of 2287 , the T - 51b seems to still be in use in the West Coast Brotherhood of Steel , while over in the East Coast Brotherhood division , it was entirely replaced by its more advanced successor model , The T - 60 armor . Additionally , after the defeat of the Enclave , the Brotherhood has the ability to manufacture more power armor , according to Paladin Danse . Appearances . T - 51b power armor and its hardened version appear in both " Fallout " and " Fallout 2 " ( and was to appear in " Van Buren " ) , while the latter also introduced the Enclave ' s advanced variants . The armor also appears in " Fallout 3 " , where the original T - 51b is unique , as the local chapter of the Brotherhood of Steel mostly wear the first successful model of power armor ; the T - 45d . A winterized combat version is used by American troops in . As shown in both " Fallout " and " Fallout 2 " , T - 51b models seem to exist in greater abundance along the West Coast and in New California compared to their availability in the Capital Wasteland . Even in the Pentagon , ostensibly the heart of American military power , most if not all power armor suits were of the T - 45d line . " " shows the T - 51b power armor only once in the introduction to the game , and the Eastern Brotherhood power armor ( called simply power armor there ) is used instead in the game , including an advanced version , years before the development of the Enclave ' s new model . In " Van Buren " , the appearance of the armor was slightly changed . Here ' s how J . E . Sawyer justified the decision : The T - 51b appears in greater numbers in " " , appearing on Brotherhood of Steel patrols and sometimes appears mixed with due to a bug . The T - 51b returns in " Fallout 4 " , and is now reliant on fusion core s for the majority of its functions , along with a functioning headlamp and multiple other modifications . T - 51b and other T - 51 types are commonly found throughout the Commonwealth , and provide substantial protection to the wearer .