To calculate the overall star rating and percentage breakdown by star, we don’t 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.
The converter does not work for what I purchased it for. I wanted to use a cigarette lighter powered vacuum cleaner indoors and had thought/hoped that the converter would allow this (using iPhone charger pack or mains charger plug) ... but didn't work at all. I don't know whether converter is incompatible or just doesn't work.