The back-mounted TX-28 MicroFusion Pack generates 60,000 Watts to power the HiFlo hydraulic systems built into the frame of the suit. Even without any pieces, a Power Armor frame provides a variety of advantages, like increased carry weight, greater melee damage and the elimination of falling damage. The basis for all power armor suits, one can't wear power armor without stepping into the frame.
More importantly, it boasts a standard fusion core interface allowing them to be powered from any core found in the wasteland. Powered by a back-mounted TX-28 micro-fusion pack generating 60,000 Watts of energy, the HiFlo hydraulics inside the frame increase the operator's strength and carrying capacity.
The West Tek internalized servo system is the standard chassis for all power armor series.