this is my first big purchase for myself in years! i have been so excited to receive this in the mail that i was watching the tracking info everyday since i ordered it. i was looking for a way to track my health without wearing a wristband. (i have sensory issues so wearing a watch everyday can be challenging for me.) thankfully this ring is sleek and lightweight. my main concern around these wearable health trackers is the subscription that comes with them. i would be insanely upset if i paid $200+ for the ring itself, just for it to be unusable because *surprise* theres a monthy subscription.thankfully, RENPHO does not follow that business model. Information the Lynx smart ring tracks: • heart rate & heart rate variability • SpO₂ (blood oxygen) • stress levels •sleep stages and score • activity tracking for walking, running, hiking, and swimming overall, i am impressed by this ring, even though i've only worn it for a day.