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.
It is a very good product. The supplier obliged and interacted to make sure that the problem was solved and that it fitted perfectly. It is a blessing in a dusty environment. Slip it onto a duty bed and you are not troubled by dust and mites.
The seller claims it to be waterproof. This product is everything but waterproof. I bought this product for use for my infant. But during every single use the fluid has sipped through it. The product is namesake and doesn't do justice to it's product description. Advise others not to buy.