This custom GPU server chassis which supports 4 x GPU cards is made for top of the world medical equipment manufacturers. 

Application: GPU Computing Server for Medical Equipment 

Key Features: 
Dual Intel Xeon processor in proprietary MB 
4 x dual-slots GPU Card 
3 x normal PCIe Card 
Support 4 x 2.5” hot-swappable HDD with off-the-shelf HDD cage 
Rackmount ear brackets on rear panel 
1+1 Redundant PSU 

Spec
Chassis Material: SGCC Sheet Metal 
Form Factor: 4U Rackmount with Proprietary MB 
Power Supply: 1+1 Redundant PSU 
Drive Capacity: 4 x 2.5" Hot-Swappable HDD 
Expansion Slot: 4 x Dual-Slot GPU Card;3 x Normal PCIe Card 
Cooling Fan: 3 x 120*120*25mm Fan 
LED Indicator: Power on, Reset, 2 x LAN 
Button: Power, Reset 
Dimension(DxWxH): 550 x 440 x 177mm