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.
I am so glad I purchased these sleeves so that I can store my set indoors during the winter. My only complaint is that I received only 1 sleeve cap. I left a message with manufacturer and they never returned my inquiry.