This product is either discontinued or we cannot get that from suppliers.
Noctua NF-A20 200mm 800RPM PWM Fan, Fan 200x200x30mm, 800RPM, Airflow 146.9 m3/h, 100.8 m3/h (with L.N.A.), Acoustical Noise 18.1 dBA, 10.7 dBA (with L.N.A.), Bearing SSO2, 4-Pin Power Connection.
The NF-A20 is a highly optimised, premium quality quiet 200mm fan. Featuring an AAO (Advanced Acoustic Optimisation) standard frame as well as sophisticated aerodynamic design measures such as Flow Acceleration Channels.