The NA-FK1 is a second fan kit for the NH-U12S redux CPU cooler. Upgrading it to a push/pull-style dual-fan setup makes it possible to further improve cooling performance or to reduce noise levels by having two fans running at lower speeds. The kit includes a second NF-P12 redux-1700 PWM fan, anti-vibration pads, fan mounting clips, a 4-pin PWM y-cable as well as two Low-Noise Adaptors – everything you need to boost the efficiency of your NH-U12S redux!