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.
A really fantastic grater that has definitely taken my cooking skills to the next level. So far I have used this grater for zesting citrus and finely grating parmesan cheese and garlic and it is fantastic with all. It is really easy to clean and because of the direction of the blades you don't cut yourself when cleaning it up.