KINGWEAR KW01 bluetooth Calling Heart Rate Sleep Monitor Calculator Stopwatch IP68 Waterproof Smart worth to buy? Thanks for it if those of you who have purchased KINGWEAR KW01 bluetooth Calling Heart Rate Sleep Monitor Calculator Stopwatch IP68 Waterproof Smart could share about what you think of the product. I would love any extra info, as it is quite pricey as $56.47 and I just want to know it is good before paying for it.