HP Vectra XM5 3 Supplementary Manual page 24

Front Accessible Mass Storage Shelves
The PC has three front accessible mass storage shelves:
slim top shelf (1-inch high) for 3.5-inch or 5.25-inch devices
half-height middle shelf for 5.25-inch devices
slim bottom shelf (1-inch high) for 3.5-inch or 5.25-inch devices.
The additional 1-inch high bottom shelf can be used to install any of the new 1-
inch-high front-access devices. Tape drives and 5.25-inch flexible disk drives are
now becoming available in the industry with the 1-inch high form factor.
The following mounting rails can be ordered for front access drives:
D2880A 5.25-inch disk drive mounting rails (five pairs of rails)
D3566A 3.5-inch disk drive mounting rails (five pairs of rails).
HP Vectra XM 5/xx Series PC Familiarization Guide
Features 24
1 Product Overview and