D13 1.3 inch OLED Color Screen Smart Bracelet IP67 Waterproof, Support Call Reminder/ Heart Rate Mon worth to buy? Thanks for it if those of you who have purchased D13 1.3 inch OLED Color Screen Smart Bracelet IP67 Waterproof, Support Call Reminder/ Heart Rate Mon could share about what you think of the product. I would love any extra info, as it is quite pricey as $11.13 and I just want to know it is good before paying for it.