[over] CM Hyper 212+ for $25.17 shipped.

[SteelyKen]

Most heatsinks include one fan attached so that air is pushed through the fins and, depending on case design and the cpu cooler orientation, towards
either the rear or ceiling case exit fans. A push-pull installation simply adds another fan to the other side of the heatsink blowing in the same direction as the first.

 

[brownstone]

Got it today! Installed and at full load (3.3oc at 1.375v on my 720be) my temps went from 54C to 40C. Aside from slicing my knuckle open on the heatsink, I'm pleased!