This product is either discontinued or we cannot get that from suppliers.
Noctua NF-A6x25-PWM 60mm PWM 3000RPM Fan, 60x60x25 mm, Mounting hole spacing 50x50 mm, Connector 4-Pin PWM, Bearing SSO2, Blade Geometry A-Series with Flow Acceleration Channels, Frame Technology AAO, Rotational Speed (+/- 10%) 3000 RPM, Airflow 29.2 m3/h.
The NF-A6x25 PWM is a highly optimized, premium quality quiet fan in 60x25mm size. The PWM version sports Noctua's custom designed NE-FD1 IC for fully automatic speed control via 4-pin fan.