Fan top shutters are manufactured in the frame of your choice. The movable louvers are connected from the hub directly into the frame. Fan top shutters are generally attached to the opening permanently. In order for them to be removable they will need to be installed with magnets or button catches. Fan top shutters are available as a ½ circle or as an eyebrow. The bottom of the fan top shutter can be manufactured as bottom with frame or bottom with a base.
We use the fan top shutter with the base to sit on top of the shutter below - and we use the full framed fan shutter for the stand alone window.