An audience of gerbils probably doesn't need to be told this, but few companies take fans more seriously than Noctua. As proof, I present the fact that the company spent the last five years developing its latest fan design: the NF-A12x25. In the process, the company used computational fluid dynamics, laser vibrometers, and acoustic imaging to figure out that existing fan materials just weren't going to cut it. Ultimately Noctua invented its own material and created what it says is its best fan ever.
The new material is a liquid crystal polymer called Sterrox, from the ancient Greek στερρός. It means "hard" or "rigid," and it represents the fact that that Sterrox is mostly immune to so-called impeller creep. You see, the new NF-A12 fans have the company's tightest tolerances ever—just 0.5 mm of blade tip clearance. That's the distance between the fan blade's tips and the frame. Noctua says that choice was made possible through the development and usage of Sterrox because conventional polymers would end up expanding and scraping against the frame with such a tight blade tip clearance.
The end result is that the NF-A12 is Noctua's best-performing fan across the widest variety of scenarios. Noctua CEO Lars Strömbäck says that even though the company's F12 fans have higher theoretical maximum air pressure, and that its S12 fans have higher theoretical maximum airflow, neither of those values actually come into play in most real-world PC cooling situations. The company says that the A12 will offer superior performance in both characteristics when used on PC cases, air-cooling heatsinks, and liquid-cooling radiators.
If all this sounds familiar, it's probably because we saw these fans at Computex last year. They were still under development then, but now they're finally available. The new fans will replace the P-series fans that are the company's extant "do it all" fan, but those too will continue to be available under the "redux" brand. The promised 140-mm version of the A-series fans hasn't shown up yet, but the NF-A12x25s are available in speed-controlled PWM, full-speed FLX, and speed-reduced ultra-low-noise variants. Gerbils needing fancy fans can pick up any variant at Amazon for $29.90.