An enclosure for electronics includes a chassis and an interface connector positioned within the chassis and configured to provide power. A fan shelf module is received within the chassis and has at least one fan to provide air flow through the chassis. The fan shelf module includes a pinout connector along a horizontal or vertical line of symmetry and configured to engage the interface connector and receive power therefrom, such that the fan shelf module is selectively installed in one of two opposing directions allowing a fan air flow direction to the chassis to be selected as either pulling air or pushing air through the chassis depending on the installed direction of the fan shelf module.