HP P29158-002 memory cooler with bumpers is a replacement cooling component listed for the HP Z4 G5 Workstation. It is intended for the workstation’s memory area, helping provide cooling there as part of the system’s thermal design.
The listed part name specifies bumpers, so this is the Z4 G5 memory cooler variant with bumpers. It is identified separately from the CPU cooler, making its role clear: it serves the memory cooling position rather than the processor cooling position.