I ordered this fixture (remodel unit)to add some needed light in my shower. It was easy to install from below the ceiling, a good thing because our attic clearance is minimal in the area. I just drilled the hole, attached the wires according to my husband's directions, and pushed the unit into the opening. It attached permanently by pushing the 2 arms on either side of the housing up so that they fasten to the sheetrock. Then I just snapped the trim into place.
The unit was well made, the trim looks great, and it does a very good job of lighting my 3x4 foot shower. I would recommend the housing for any remodel installation with any of the trims available.