The bright red LED display makes this among the easiest to read pocket pulse oximeters in the trade. If you think that this is a minor detail, try reading one of the LCD display models from the competition in low light or bright light with sunglasses. I am an athlete and wilderness first responder and use this item in field settings where the extra seconds to get a good reading is a nuisance at best, but ease of use is always a good thing when other distractions are present.
I dinged this unit a star on accuracy for a couple of reasons: first, it struggles to get a pulse in really bright sunlight. My guess is that enough extraneous light leaks in around the finger "cuff" to prevent the sensor from getting a fix on the pulse. Second, it is near impossible to get a reading on heavily pigmented or calloused skin. I'm the guy whose TouchID programming might last three or four days at best because of callouses and cracked skin (landscaper and rock climber) so, yes, this is an issue. Third, if your fingers are cold or wet or you suffer from Raynaud Syndrome you WILL NOT get a pulse reading and hence, get no pulse ox reading.
On the plus side, this and other pocket pulse oximeters are cheap, light and run forever on two AAA batteries. It's a worthy investment for the athlete measuring oxygenation or for the first aid jump kit, just be aware of the limitations.

Update 6 months later. I loved this because it was fast, only used it probably a total of 25 times since I bought it during respiratory bouts. This week had to change batteries, and it is impossible. I've tried every finger (they say warm them up if not reading), trimmed my nails a tad (they said long fingernails can interfere). and now it sucks. Blinkety blinkety and no readings. This is my second meter tried out. The first one (returned) had too tiny of writing on it and told me everything but the kitchen sink, most of which I did not need nor understand. This one is simple. Big red display and only two readings, oxygen at the top.

Well-designed oximeter. We have another oximeter that we had got calibrated at our doctor's office. The new one gets readings that are very close to the calibrated oximeter. Thanks for an excellent product.

Excellent buy! Find out EARLY if you may be developing CoVid pneumonia: check daily or oftener. Thermometer sees infection first, but oximeter spots drop in lung function. Why vital: CoVid-19 targets surfactant cells. Almost all patients have little/no tightness, pain or shortness of breath until infection has spread widely. May also cause reaction that boosts blood's clotting rate: likewise dangerous. (Caveat: everyone has *slight* variations in blood O2, per overall health and age, activity level that hour, etc. O2 falls as you run Ironman, etc.) Gizmo: batteries' positive terminals on same end, readout's characters perfectly clear and legible; display sequence is a cinch to master; item comes with lanyard. It's all sturdy and well-made, and earned high score for accuracy in an objective review. (As per note in "Retirement" magazine, users of any brand or device model must ensure proper fit for accuracy if finger is not any average-sized. Significant variations in dimensions of sensor panel a given manufacturer builds into this model vs. that one, or variations between one manufacturer's oximeter/pulse-rate device and another's. ZacUrate appears to be best of inexpensive and midrange models, in terms if accurately reflecting user's O2 saturatiin and pulse rates.)

Got it overnight to measure wife's oxygen and pulse as we navigate her serious condition. Works great and gives us comfort to know that the pulse and oxygen stay in acceptable range while we go through this. Doctor gave us the ranges to monitor and the piece of mind is comforting.