I bought my mom a Xiaomi Mi Band 2, so her old optical heart rate Mi Band landed in my hands. I tried wearing it on my right wrist, since my left one already has a Moto 360 2nd. Honestly I wasn’t expecting much from this thing. I even installed the pairing app on my backup Nexus 5X. My demands were low — mostly I just wanted to see if it could track my sleep quality, and whatever else it did, whatever. Since it has an alarm function, I set an alarm on it identical to the one on the Moto 360 2nd. The original band strap was disgustingly filthy, so I swapped on a spare yellow one that came free when I bought the thing.