Oxygen Pro Oximeter for fast, reliable heart rate and blood oxygen monitoring at home. A compact and portable design which can easily be packed and taken out with you. A clear LED screen clearly displays both readings. It takes 2 AAA batteries which are included. The oximeter measures your heart rate and oxygen level in your blood. Measuring the oxygen levels in your blood can be helpful in monitoring certain conditions. Low oxygen levels may cause shortness of breath and a rapid breathing rate. The oximeter lets you monitor your saturation rates from home to keep an eye on your levels and if they are staying within your normal range.