Now there is a dependable and easy way to spot check your oxygen level & heart rate measurements for your daily needs, ez-read from all 4 sides with simple one button operation, hd 2 color oled display, comfort-fit, textured padding, adjustable brightness, strong slip resistant clip, auto power off when finger is removed, low power consumption, low battery indicator, non invasive, warranty: 1 year warranty.great for exercise, mountain climbing and aviationmeasuring range for spo2: 70-99%measuring range for pulse rate: 30-235 beats per minutepulse bar graph indicates the intensity of the pulse signalhighly reliable measurements spo2 accuracy: spo2 range from 70%--99%, ±3%; from 69% and lower, no reading available.pulse rate accuracy: from 30-235 beats per minute, ±2% or 2 beats per minuteresolution: for spo2 - displays each 1%. for pulse rate- displays each beat. as with all oximeters, for best results, keep hands still while taking a reading. fingernail polish and acrylic nails interfere with oximeter readings and result in inaccurate readings. note: this device is not intended for self diagnosis and does not replace a doctor's visit. This device is FDA approved