This Noctua fan is just for replacement in Enhance Electronics ENP-7760B or Silverstone FX600 (Identical PSU manufactured by Enhance Electronics). 
The fan has been customized with 1.5Ton die crimped 2mm pitch pins and header to fit, the lead is customized to fit and 2 holes are reamed to enable perfect fitment in these power supplies. Furthermore 2 screws are included to complete fitment as the through hole Diameter of Noctua fans is larger than the original so the original screws cannot be reused. 

Whilst the fan runs the PSU cooler than original it's important to understand that Noctua fans push less air than stock, almost half as much as the stock fans. 
This means it's limited in not being capable of running the upper power levels of the power supply. We recommend it for applications where the continuous max power load is 400W or less. We can help validate this if required.

Please feel free to contact us with any question or concerns prior to ordering. Also note our fans are not retail packaged as we largely integrate them in to ENP-7660B in house so we take integrator models from Noctua that don't have all the packaging to save on generating unnecessary plastic waste.