Amazon calculates a product's star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers and factors that establish reviewer trustworthiness.
Didn't reach the expectations. Packing is not up to the mark. It not worth the money paid. Had ordered 3 masks out of which there was double filters which was looking odd. It shows that packing was not done with care.