One of the best pulse oximeters models presently available is the Santa Medical SM-110 finger pulse oximeter. This unit combines both advanced medical technology and the features most consumers want. And consumers, by the way, have given the SM-110 excellent reviews.The SM-110 finger pulse oximeter is powered by two AAA alkaline batteries. With new batteries, you can expect this unit to function for thirty continuous hours with a high degree of accuracy. The battery life on the SM-110 is average for home medical pulse oximeters designed for personal use.