Cit s503 2 x usb 20 2 x usb 30 micro atx desktop case the cit s503 slim desktop case is notably strong for its modest size creating the perfect case for system integrators the cit s503 features a full tool less design with 2 x usb 20 and 2 x usb 30 and a quick release oddhdd housing system for fast installation with minimal effort the included base allows for vertical installation of the s503 the cit s503 supports micro atx or mini atx form factor motherboards and with its low