The Delta AFB0712HHB-PWM, 70x15mm-4pin PWM+Tac Sensor, Extreme Hi-speed 4300 RPM, 37.54cfm.
With the PWM fan connector you can let your motherboard keep this fan running at minimal speeds and still have the high end for those times when you really need it.
The Evercool 70mm x 15mm High Speed PWM Fan mounts on standard 70mm fan holes. This fan puts out a large volume of air for it's size. This fan uses energy saving PWM, and has a 4-pin PWM connector type.