Compatible with Raspberry Pi 4 Model B --- This 19" 3U rackmount with Micro HDMI to HDMI Boards are only for Raspberry Pi 4B board, supports 1-14 Units of Raspberry Pi 4 Model B.(Raspberry Pi Board NOT Included) Standard 3U Size ---19"×5.11"(482×130mm). Fully compatible with 19" server racks, had no issue plugging this into the 3U rack space. With TF card to FPC Boards & Micro HDMI to HDMI Boards --- The TF card to FPC boards with Flex cables will relocate SD card slot; The Micro HDMI Adapter Boards convert the Micro HDMI to HDMI and relocated HDMI ports to make all IO ports on one side; With Good Heat Dissipation Effect --- This kit includes 14pcs fans and heatsinks will make Raspberry Pi Board cool. Package Inlcudes:1 x 3U 19" Rack Mount for Raspberry Pi 4B;14 x FAN DC Board; 14 x Micro HDMI to HDMI board; 14 x TF card to FPC board; 1 x Quick Guide; 14 x Cooling Fan;14 x HeatSinks; 14 x Flex Cable; 1 x Screwdriver