4U IPC Chassis support Micro ATX, ATX, 12" x 13" Motherboard, and Easy-to-open Top Cover Design. Lockable Front Panel gain more security. The redesigned RM-4U455 incorporates high flexibility and high availability in a 4U form factor. From high density Raid storage, Data center server to high performance super computing, RM-4U455 can handle it all. The 7 PCI slots support PCI, PCI 64bits, AGP, and PCI-Express add-on cards for additional expansion and upgrades. RM-4U455 is a high scalable and multi-functional rackmount chassis. Compatible With Most OTS Sliding Rail