First time buyer of smart rings, I’ve been using the Colmi R09 smart ring for 5 days straight with all tracking features enabled through the app, and I'm impressed. The battery is showing 60%, which is excellent. The heart rate monitor is almost identical to my Galaxy Watch 4, providing accurate readings. I love the added skin temperature monitor, which was the main reason I chose this model over others. The sleep monitoring is a bit off though, with an average 30 minute discrepancy compared to my watch as it starts recording after certain amount of time when no movement is detected which could cause some possible false readings compared to the watch which detects heart rate lowering to detect sleep. The ring is lightweight, comfortable to wear, and the size received matches the listing chart perfectly. Overall, I think this is a solid, affordable health monitoring device. I definitely recommend. Will definitely buy more from this store in the future when new releases become available