- You cannot add "Silverstone SST-RM44 4U Case Front Secure Lock Supports Upto SSI-CEB MBD - Supports 360mm AIO - 8x PCI Slot -2x 3.5" Internal (compatible with 2.5" x 3) - 4x 2.5" Internal - CPU Cooler Support Upto 148mm - Front I/O: 2x USB - 1x Type C- AT" to the cart because the product is out of stock.