direction of fan on heatsink

[tornadog]

I got a thermalright venomous-x heatsink, and a 120mm noctua fan. Should the fan blow air into the heatsink or blow out?. At the base of the fan there are 2 arrows probably pointing the direction of airflow.

 

[jjmIII]

Push air into and through the heatsink.

 

[MagnusTheBrewer]

It's always easier to blow than suck.