The Valerie (MAO1) series are axial exhaust fans suitable for air extraction directly to the outside or via short ducting. They have ball bearing motors for long life and come in 2 sizes. They can be mounted in walls, ceilings or windows.
When wall or ceiling mounted, just the front part of the fan is used, the spacers are not needed. For wall mounting, you will also need an external vent.

This model has an electric shutter at the front to stop air escaping or coming in from outside. The shutters open automatically (and smoothly) when the fan is operated.