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.
Great build quality. Sound quality is also good over short distances. However, the range is not advertised. In urban area, range is only 300 mts whereas in open area, range is about 700 mts only against the claimed1.5 Km. Still, it is lots of fun & actually useful while out camping or trekking in wilderness.