Review on XOSS X1 Bike Speed and Cadence Sensor: Wireless Bluetooth 4.0 Computer for Accurate Bicycle Speedometer (2 Pack) by Mike Groover

I bought two so now have two extras but my wife can use one and I have a backup. Sensors received in one day. They were easy to set up and install. I was using the cyclemeter app on an iPhone 8 with the latest IOS and it was trivial to pair it with the cyclemeter via bluetooth. The paper manual instructions were fine, but the online instructions in the videos on Revain were even better. Do not connect sensors via Settings/Bluetooth. Use your app, in my case Cyclemeter. I liked my Wahoo sensors but after two sets that lasted less than two years I decided to give these a try even though I thought they were more expensive. Turns out they were cheaper. So far, I am very satisfied. Update: 09/30/2020 This morning my cadence sensor stopped working. The cyclemeter app didn't show any cadence and Settings/Bluetooth didn't find the sensor either. I changed the battery several times but the light didn't blink. The cadence sensor was dead. I then checked the speed sensor which is working fine. I took the battery out and put it back in. The light flashed blue, indicating he was now in cadence mode. I decided to replace the battery with a new one as the voltage was a bit low, around 3 volts. The block was not flashed when a fresh 3.2 volt battery was installed. Now the speed sensor is dead too. I checked the battery contacts, they are clean and shiny, and tried bending them a bit for a stronger contact. I must be doing something wrong but I've run out of things to try. I sent a message to the manufacturer, maybe they can help. Update 10/01/2020 I've been desperately trying to get these sensors to work. Even though my 2032 batteries were 3.2 volts, I bought brand new batteries. New batteries solved my problems. I immediately got a single flash of light, red and then blue after I put the batteries back in. I tested them on a bike (only on a bench so far) and the cyclemeter app on my iPhone showed both speed and cadence. All is well. From 5 stars to 1 star and now back to 5 stars. As usual, operator error.