Compaq Pentium Pro 166 MHz 512k (219421-001) Processor Upgrade Kit for Compaq ProLiant 5000 servers. This is an additional upgrade Pentium Pro 166 MHz 512k CPU for Compaq ProLiant 5000 servers. It is used to expand to 3 or 4 processors. The upgrade may also require the dual CPU processor board. This unit is brand new, Factory Sealed in the original box.