Fujitsu Primergy BX920 S4 Upgrade And Maintenance Manual page 119

Expansion cards and backup units
The figure below shows the two kinds of unpopulated carriers for mezzanine
cards. All installation/removal procedures are identical for both carriers.
Figure 26: Carrier for mezzanine cards with two "x8" riser cards
Figure 27: Carrier for mezzanine cards with one "x8" and one "x16" (2) riser card
I
Note the numbering of the mezzanine card slots.
Upgrade and Maintenance Manual 119
BX920 S4