The SleepU is a handy and compact SpO2 monitor. I use it to monitor my levels supplied by an O2 concentrator. A few small gripes:
1) I have large hands and long fingers. The ring would fit well on the middle segment of my index or middle finger, but the cable is too short to reach the watch unit. I'm forced to wear the ring on the largest segment of my middle finger(quite snug) and wear the watch fastened very loosely so that it rides low on my wrist and the cable can reach. It works, but could REALLY use one more inch(better 1-1/2 in) in length.
2) I would have liked to see standard USB-micro connectors used instead of a proprietary system, so that a longer cable could be purchased, including USB-C on the host end. This is almost inexcusable, given the nearly identical dimensions. I suspect many customers have wasted their time and money buying USB-micro cables. At least make a note in the manual that is is NOT compatible with USB-micro.
3) When connecting to a PC, the data download is very quick, yet the display still indicates data interchange, rather than switching to the charging icon, leading to having the unit hanging on the laptop for much longer than needed.
4) The GUI. I am accustomed to laptops with touchscreens that scroll on-screen, with a thumb or finger. Up and down, side to side. I often scroll between the header stats and the data displays, and it is very tedious to use the mousepad to maneuver to the scroll bar(s) to move the display. This should be a SMOP (Simple Matter Of Programming).
Overall, even with a few shortcomings, the SleepU is a very useful tool for anyone with breathing issues like sleep apnea. Recommended.