XOSS X1 Heart Rate Monitor Armband Bluetooth & ANT+ Wireless Heart Rate Health Accessories Fitness Tracker(Armband)

Bought it for perceived comfort over cheat heart rate sensor, and paid a premium for that - convenience is a plus.The first device I received was inaccurate and inconsistent. It appeared to pair with cadence sensor, other times the heart rate would suddenly drops to half of what it should be. Tried turning the sensor on after starting trip for better pairing but that didn’t work at all times. Tried different locations on the arm but couldn’t find a single location where the readings were consistent. Did verify readings against Apple Watch and polar chest strap.Poor product.After that not so good experience, I called Amazon to return device but decided to accept a replacement and give xoss armband hrm another chance. The replacement worked as expected right away with no issues. Clearly the first device was defective. I have been using the replacement for a couple of weeks now - the readings are consistent with my Apple Watch, pairs quickly with xoss bike computer and stays connected. Very satisfied with the product.Updating rating to 5 stars for function and customer service.

I like the comfort of the item. It monitors my heart rate as advertised.

I've been using this external heart rate monitor for two months now on a daily basis. I use it with a Garmin Forerunner 645 (while running), XOSS G+ cycling head unit (for outdoor cycling), and my iPad Pro when I use Rouvy (for virtual cycling).There are two significant advantages to using an external heart rate monitor:1) It provides far more accurate readings for running than the Garmin watch worn on the wrist.2) It can project heart rate data to multiple devices simultaneously, such as the cycling head unit and the Garmin Forerunner.I much prefer it over the chest strap heart rate monitors I've used for the past few decades. Those chest straps would often slide down my chest, restrict my breathing, be uncomfortable, and provide inaccurate readings if the electrodes weren't moist. As far as I can tell, this armband heart rate monitor is just as accurate.The battery life is excellent. It's rated for around 20 hours, and from my experience, that rating seems credible. I work out for about 7-10 hours per week, and I've never received a low battery warning since I charge the monitor once every week or two.However, the heart rate monitor isn't flawless. In nearly 70 uses during running, I've encountered "cadence lock" about 7 times. "Cadence lock" occurs when the signal noise from a runner's arm swing is misinterpreted as a heartbeat, resulting in heart rate readings close to (but not necessarily exactly matching) your cadence, such as 160 bpm. This is a common issue with most optical heart rate sensors. Placing the heart rate monitor above your elbow and next to your bicep helps reduce this issue compared to the wrist location of the Garmin watch, but it still occurs occasionally.In my experience, it typically happens at the beginning of the run when wearing a singlet. Sometimes, turning off the heart rate monitor and then back on (easy to do mid-stride) resolves the problem. However, sometimes it doesn't, and the heart rate starts reading correctly only when I warm up.My theory is that on those occasions, my body was cold, and my blood vessels were more deeply embedded under the skin, making them harder to read. If that's correct, warming up or wearing sleeves over the heart rate monitor on cold days should help alleviate the issue.I tried using the heart rate monitor in a pool once. The "swim" tracking function of my Garmin didn't provide a screen for viewing my heart rate, so I can't confirm whether it was working underwater. However, I can confirm that no damage was done to the heart rate monitor, so it is indeed waterproof.

Very happy with this product. I purchased to use with the DDP Yoga app as I was using a chest strap, which was uncomfortable to use during certain moves and poses. This HRM being an arm strap offers more freedom and I can maximize my workouts. I had no problems getting the device to connect to the DDP Yoga app. The heart rate being reported by the HRM is very, very similar to what I was getting from the chest strap - so accuracy seems to be very high. Battery life is great. Comfort from the soft strap is excellent. I wear it on my upper forearm and it fits fine. No complaints so far, does everything I need it to do.

Edit after several runs: this device suffers from periodic "cadence lock" which means that that HR reading locks onto your cadence rather than your heart rate. This has now happened intermittently during my last two runs, once on the treadmill and once outside. My heart rate while running normally averages 130bpm, but now periodically displays 180bpm which is not possible (my max HR is about 170) and corresponds to my running cadence. This has been a problem with optical HRMs in the past, but most brands have overcome the problem with software updates. I'm still keeping it at 3 stars because it does not have this problem when used for cycling.Original review below:I have only had this for two days, but so far it has exceeded my expectations. I decided to take a chance on it since it is less than half the price of the 'name brand' options from Polar, Wahoo, and Scosche. Note that this XOSS unit appears identical to the higher-priced "Coospo" unit for sale here on Amazon.In order to test the unit I first ran with it on my normal outdoor route, and the readings are nearly identical to my chest strap. It also responds fairly quickly to changes in pace and grade. Overall I am very pleased with the accuracy, especially compared to wrist-based monitors which have never worked for me. Note that I am wearing this unit on my upper arm, with the sensor about midway between the top of my bicep and the outer arm.To test the battery life, I wore the unit for 24 hours continuously and I'm please to say it was still working after a full day! So the initial battery life is even better than the claimed 20 hours. The only apparent weakness with this watch so far is the strap, which seems very flimsy and is likely to stretch and weaken with use. I'll update the review after more use and testing over the next few weeks.