For an essential reduction of the noise level, the Fans can be built into a soundbox - which also increases the weather protection of the Fans.

The soundbox surrounds the Fan 100%, which means that the noise from the motor is reduced. A duct silencer on the extraction pipe is not necessary - this is built into the soundbox at the front.

An air inlet with a diameter of 80 mm on the motor side of the box supplies the motor with cooling air. Box and Fan are assembled without the use of tools.