These are the B12-2 1300RPM and B12-3 1900RPM 120mm high end case fans. I bought four of the B12-2 first, returned them and replaced with four of the B12-3, read on for details. For manufacturer specs, see here. Noiseblocker NB-eLoop B12-2 Review Initial impressions The packaging comes with rubber inserts which absorb vibrations as well as separate the blades slightly from the mesh or filter next to it. Should come in handy. The cord is modular, a short and a long cord is supplied and they can be combined for an extra long cable. Very nice addition for case cable management. And I just love how it looks - white on black when installed in my Fractal R3, just like the stock fans. The B12-2 is much quieter than the 1000RPM Fractal Design stock fan. Virtually silent in comparison, testing on an open air bench (just my mobo on a piece of cardboard). It is also noticeably quieter than Silverstone AP121 1500RPM. Attaching the fan to my new Bitfenix Hydra Pro controller, I don't hear any difference between the highest and lowest settings until I put my ear right next to the fan. I can confirm that the difference in airflow is significant. To my disappointment, however, the fan doesn't actually run at 1300 RPM. BIOS reports about 1100-1150RPM, and HWMonitor agrees. I may have to return these for the 1900 RPM versions which I can then downvolt to 5V for quiet computing and run at full speed for heavier overclocking, we'll see once I test the fans in my case. CPU temperatures Heatsink: Scythe Mugen 2 on open air bench Comparison fan: Scythe Slipstream PWM @ 1350RPM CPU: i7 920 @ 3.36GHz @ 1.2V. Stress test: 10 minutes of Prime95 blend Max. core temperatures: Slipstream - 66, 64, 63, 64 NB-eLoop – 70, 69, 68, 68 This is not a very good result. But we have to bear in mind that it spins 200RPM slower as reported by HWMonitor. Some of the temperature increase, if not most, is explained by this. However, the important part is that the Slipstream fan is clearly audible. Any silence freak would be quite annoyed by the 1350RPM Slipstream, even when muffled by the side panel of a silent case. With the Noiseblocker, the cooler is almost inaudible at about 50cm away from the test bench. It makes slightly more noise than without the heatsink next to it but I can't call it anything else than near-silent. Noise levels in Fractal Design Define R3 The point here is to see how much the filters and meshes affect noise levels, if at all. Front panel intake. The fan becomes audible at distance but still very smooth and quiet. Having the door open or closed doesn't seem to make any difference. The rubber inserts really help here – without them, the blades would be almost touching the filter. Rear panel exhaust. Same as above, really. It's still super quiet but not inaudible. The tone of the noise increases somewhat due to the mesh, much like with the intake filter. Conclusion These are superb fans, high quality all around. While I haven't tested many fans and have never even touched a Scythe Gentle Typhoon, I'm confident that these are some of the best case fans in the market, if not the best. The price tag (18.50 eur here, $27 at FrozenCPU) is completely justified since these are also backed by 6 year warranty. Well worth it for anyone who is interested in quiet computing and doesn't want to compromise airflow too much. However, if you've got a fan controller or like to adjust fan speeds in the BIOS, I would initially recommend the 1900RPM version. I'm going to swap all my Noiseblockers for those, and will update this thread once I get them. At the lowest setting in my controller, the 1900RPM fan should run at just under 1000RPM, slower than the already near-silent 1300RPM fan. There are also 140mm and a 180mm versions coming. The 140mm model should be a godsend for people with the Fractal Design Define R4. Thanks for reading!