This Fingertip Pulse Oximeter is designed to provide an easy and accurate way for spot-checking your blood oxygen saturation levels and pulse rate with an accuracy of +- 1%. Bright LED Display The bright LED display allows use in low light. This bright display is view-able in any environment – from dark surroundings to bright sunlight. Easy Battery Removal The quick snap-off cover allows for an easy removal batteries and takes screws out of the equation. (Uses 2 AAA Alkaline Batteries) You will see a ‘Low Battery’ indicator to signal you to replace your batteries.