HP 900 Series - Figure 2-16 B; C. Expander Motherboards Fasteners

Figure 2-16c. HP 98570A Expander Motherboard Screws
Card Guides
Card guides on the left-hand side (power supply side) of the cage just snap into place. They
may be removed by carefully unsnapping them.
Be sure they are replaced correctly, with the correct end toward the front and back of the unit.
50 Assembly Replacement