The power system unit 51404174-275 (Model# MC-PSRX04) consists of:
(1) 51404170-175 power supply housing
(2) 51198947-100 or 51109684-100 silver power supplies

This part number assembly DOES NOT include the 51103948-100 48v battery tray assembly.
MC-PSRB04 (51404174-375) includes the battery tray assembly.