Product review (2 stars): Damaged because blade was improperly mounted only on the tip of the shaft.
The blade had a "Y" shaped crack radiating from its center and it hit the mounting bracket because it was crooked on the shaft. I squeezed the cracks together and aligned the blade. I installed it, turned it on and went outside to check the vent. It only opened halfway on high. I installed the filter. I turned the fan on and the fan blade hit the filter because the blade was mounted too high on the shaft. I had to use a hammer and a large socket to pound the blade down onto the splined shaft. It works. Other than that it is quieter than the original.