Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
Very happy with the fit and over all quality of these shells. The spare screws and springs are great, I wouldn't recommend using the supplied screwdrivers as they strip the screws easily. All the screws holes were pre threaded, buttons lined up perfectly and triggers fit nice and firm.