When looking at our fans, the Front or Intake side of the fan will always be the side that has the Cooler Master Logo in the center of the blades.
The Rear or Exhaust side (the side that the air comes out of) of our fans will always be the side that houses the fan motor. You will also be able to identify the Exhaust side as you will see power wires entering the fan motor.
(the side with the guard/motor support)
Lastly, the fan airflow can be identified by the arrow markings on the fan housing.