Real nerds know the best fans come in brown.
Noctua's fans are legendary in the PC space, offering exceptional performance and reliability in a love-it-or-hate-it brown and beige colourway. Their premier 120mm fan is the NF-P12, and this model has now been discounted to £12.95 at Amazon UK. That's a lot to pay for a single fan, but these fans normally cost double - think upwards of £22 for a single fan! - so this is actually a heck of a bargain.
At 120mm, these case fans are compatible with most cases on the market from small form factor Mini ITX or Micro ATX builds to larger mid-size and full-size towers, although cases that support the same number of 140mm fans will be better served by larger 140mm fans. These fans also work well with radiators, thanks to their high static pressure.
The reason these Noctua fans are so popular is that they are extremely well balanced between performance and acoustics, with a medium-low RPM setting (1300RPM) that delivers a tremendous amount of airflow at a relatively quiet 20dB.
As three-pin (ie non-PWM) fans, the Noctua NF-P12 can be controlled by most motherboards and fan hubs but some models may just set them to 100% - which is fine for most use cases, given that their modest RPM doesn't produce distractingly loud results. Interestingly, you get low noise (1100RPM) and ultra-low noise (900RPM) adapters in the box, which set the fans to lower RPM values if you prefer them to be quieter at the expense of some airflow.
Noctua's designs tend to be fairly bulletproof, but you do get a rare six-year warranty on these fans in case anything does go wrong down the line - which speaks to Noctua's high standards for quality and customer service. Good old Austrian engineering.
If you're not fussed about RGB designs and just want great-performing case fans, this is an awesome deal on one of the best options on the market.