Oura Ring 4 Stealth, Size 10

Amazon, despite complaints, views the Ōura Ring Sizing Kit as the same or a similar item as the Ōura Ring 4, itself... thus, two DIFFERENT reviews AND ratings for two COMPLETELY DIFFERENT products. -------------- 1) THE ŌURA RING SIZING KIT / 5-Stars Ōura states that the Ring 4 sizes are NOT the same as traditional ring sizes. I did NOT break out my Ring Sizing Loops to determine the veracity of that statement because the cost, of the Ring 4 Sizer, on Amazon is applied as a credit towards the cost of an Ōura Ring 4 WHEN purchased via Amazon. I will say that there is perhaps a little difference, compared to traditional ring sizes, but I'm not sure that it's much because I ended up with the ring size that I thought would work. Interestingly enough, size 10 that I expected for the middle finger was a perfect fit for the Index finger, which is normally a traditional 9... so there is some difference in the sizing and I wholeheartedly recommend procuring the Ōura Ring 4 Sizer BEFORE purchasing the Ōura Ring 4. NOTE that the Ōura Ring 4 Sizer does not work for all Ōura Ring models, so anyone deciding to purchase a previous iteration of the Ōura Ring, due to cost decrease and/or a Sale, will need to utilize the correct Ōura Ring Sizer for the model ring chosen. If there is a question of Sale or Discount Pricing, due to the delay from checking ring sizes, then I suggest an online Chat with Amazon Customer Service representative to make sure that you can lock in any discounts to use after verifying the correct Ring size. FYI - Ōura recommends wearing the sizing ring on the finger that will bear the ring, in order to become accustomed to the ring size/feel and to see how well it fits throughout a normal day. I followed that advice and I believe that everyone should do the same. ---------------- 2) Ōura Ring 4 / 1-Star First, even with the ring sizing kit and wearing the sizer non-stop until the Ring 4 arrived, the size of the Ring 4 in only whole sizes proved inadequate. My hands clearly fluctuate enough in size to be an issue, regardless of the finger or hand that is used. Next, the heart rate (HR) was always available and showing in the app, signifying that the Ring 4 was measuring the HR, HOWEVER, the app called to show the graph of the HR for over two (2) weeks, meaning there was no history nor any assessment available. Next, the Sleep function, even with learning curve, seemed to function out of the box, HOWEVER, after the first recharge of the Ring 4, there was an issue with accurately recording start and stop points of Sleep AND eventually the app would show No Sleep Data AFTER uploading/updating UNTIL THE NEXT day. There was no event showing for sleep ALTHOUGH the Ring 4 clearly annotated the Start of the Sleep period the previous night. Next, even after more than three (3) weeks of use, the app has failed to graph the Blood Oxygen Saturation, in spite of showing the data observed and available to see at any given moment. Again, I find this to be very odd and indisputably useless to the user. Next, the App is full of "flash" or substance but in terms of a quick overall view of all the numbers, like most Apps, no such uncluttered view can be found. While the plethora of information and links is appreciated, the search to locate immediate data numbers across all items is tedious, frustrating and unappreciated. To provide an analogy, it's like having to read an entire book to search for and locate the Synopsis of the book. For those who aren't into books, then it's like watching a TV and THEN SEEING the Preview for the show that you just watched. I and most users seem to prefer a Table of Contents approach where the Raw Data is shown and then you can click to go to the Analysis, Assessment and Suggestions for that particular Biometric. In short, the App's interface is beautifully flashy and showy but about as useful up front as a Show Pony on a crop farm. That makes it overwhelming, even to those who are focused readers and moreso to the vast majority who are not. Finally, many details and assessments are NOT available for anywhere from four (4) weeks to three (3) or more months. While understandable, it makes it impossible to fully assess the personal value and utility of the Ring 4 in the 30-day period for returns. That means that the $400+ ring and the annual subscription fee is only acceptable for those with money to burn, so to speak, because all of the shortcomings or issues, even if expandable and temporary, outweigh the cost of what is actually a pretty doggone accurate piece of tech wear, resulting in the clear choice to return the ring. AND... there is one other issue to consider which is that if your hands swell, perhaps from work, or shrink, perhaps from weight loss, then your $400+ ring AND subscription become useless... until you purchase another Ōura Ring that does fit. Based on my research and experience, there are equally accurate smart fitness watches with solid Apps and reasonable insights and suggestions based on the assessment of the biometrics. Also, there is another smart ring on the market that appears to rival the Ōura Ring in accuracy, provides an seemingly identical App for all appearances seen, comes as an adjustable ring using the same high-end materials and sensor setup AND which additionally boasts being approved and classified as a Medical Grade Device, instead of a Consumer Grade Device. All of that at a far, far lower cost AND the same updates, assessments, insights and suggestions BUT with NO subscription fee. That being said, I am a Go/No-Go tester of products meaning things are either 5-star or 1-star with enough details for people to decide that my 1-star item might be good enough to be their 3- or 4-star item. The Ring 4 failed to make the grade for my needs nor was it able to justify keeping the ring to see if things improved or the money was worth the extended wait for certain observations, but it was remarkably accurate when comparing data to manual results, such as HR, SpO2, etc. There is no blood pressure data, for those in search of BP function. I am not sure that BP could be accurately obtained below the wrist at this point in technology, but maybe in the future. REMEMBER that when returning an Ōura Ring, you MUST also CANCEL the Ōura App Subscription as it is a separate financial issue from the purchase. The subscription is free for the first 30-days and a part of setting up your account before you are able to use the App, so it's an easy thing to forget. 3) Addendum -- there is a charging cable organizer with a carabineer that works GREAT for the Ōura Ring 4 charging station and cable that is available on Amazon AND IS HIGHLY RECOMMENDED. That is my next review and it will be 5-Stars. It was kind of a why-the-heck-not afterthought purchase that became an INSTANT 5-Star Should Have item as soon as I unpackaged it!!!!