Slot 2 was the server-counterpart of Slot 1, which featured larger cartridges with a triple-row of contacts in the Pentium II Xeon and Pentium III Xeon family. They were suitable for use in multiple CPU configurations, but also succumbed to Socket 370 which later replaced it.
Pentium III Xeon SL4XZ 900Mhz
This particular Pentium III Xeon came from a Compaq branded server, and its cooling solution may have been unique to the Compaq range. The retention clips are an interesting “fold over” design, and the cartridge is massive compared to the Slot 1 cartridges.
It’s interesting that they were marked 5/12V.
As it turns out, these came in a pair, and at the time I received them I thought it was unlikely I would ever meet a functioning board that would take them. As a result, I took one of the two apart to get at the insides. Visible is a large CPU underneath a heatspreader, and two VRM modules on board. Definitely advanced thinking for its time.