HP BBWC 128MB Cache Enabler (453833-001-RFB) is a battery-backed write cache module for supported server storage controllers. Its 128 MB cache provides a dedicated place to hold pending write data, while battery backing helps preserve that cached data if power is interrupted.
The OEM reference, 453833-001, identifies the module as an SA E200 part for RAID 5, 40-bit. That reference is listed for ProLiant DL160 G5, ML150 G5, ML310 G5, ML350 G4P and ML370 G5 systems.