To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
It is very useful for locations when we have to climb up on ladders to reach, such as cleaning recessed ceiling. What I don’t like is that there are no replacement filters available. Good that it doesn’t use bags.