Replaced a model 4000R Fantastic Vent with their 6000RBTA upgrade in 2009 to get thermostat, rain sensor, and power lift. Now in 2024 the blades were yellow and brittle and broke apart on the highest speed. Could not replace the blade because the old 6000RBTA used a set screw on the side of the blade hub to hold it to the motor shaft, and the replacement blades use a screw into the end of the shaft, but I had no threaded end on the old motor shaft.This replacement unit was a perfect fit. It dropped in easily, and the holes on the butterfly support bracket lined up exactly, as you can see in the photos (shown before making the wire connections). The motor can is about 1/8" shorter than the original, so there were no clearance problems with the vent lid.After connecting the wiring, it ran perfectly, with no vibration at any of the three speeds. Getting a new screen was a nice bonus. I'm very happy with this purchase and think the price is more than fair. I may buy another to keep as a spare because I can't imagine this will be available in another ten years.