This 2U RPi rackmount supports Raspberry Pi 4 B and 3 B/B+ and all other B models, and has a reserved SD card cut that allows you to access the SD card from the front of the rack when using an SD card extension cable (Not included).
This SSD plate is specifically designed to house 2.5-inch SSD (7mm/9mm) for expanding the storage of your Pi, compatible with upgraded Raspberry Pi 2U rackmount ASIN B098924W9M.
Front removable, it allows you to add/change a module directly from the front of the rack, no more need to disassemble the whole kit.