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.
Mask quality is very poor, and not as per its price. Size is small due to which it do not face and valve do not contain any filter. Only one very thin cloth behind net in front of mask. Not worth buying.