SilverStone RM41-H08 4U form factor 5 x 3.5' Hot-swappable and 3 x 5.25' server chassis Supports up to five 12 Gbit/s 3.5' SAS / SATA drives with tray-free & screw-less design Drive tray features anti-theft lock design to keep confidential information secured Supports hot-swap function Supports up to SSI-CEB motherboard Supports 7 standard size PCI / PCIe expansion slots Three 5.25' drive bays for a more flexible installation of 5.25' devices Front I/O with 5Gbps USB 3.1 Gen1 ports, backward compatible with USB 2.0 / 1.1 Pre-drilled mounting holes for easy sliding rails installation.