Someone asked us about why we dont install three screws instead of four. The three could be in like one of those light fixtures thats held in place by screws. The problem is that the two back screws cannot be easily screwed in place on roofs that have a pitch higher than 5, the roof is in the way of the driver. So we stay with the 4 screws with the back screw optional to be installed if you can get a driver back there.