Braun Fingertip Pulse Oximeter YK81CEU allows you to do track your blood oxygen levels, an important indicator of respiratory health, in a clear, convenient and comfortable way. The Braun Pulse Oximeter comes with 2 AAA batteries. When the batteries are low, the voltage symbol will display on the screen. It is a non-sterile, reusable device. It displays the percentage value of SpO2, heart rate, as well as pulse amplitude using a vertical bar graph. It featured with rotating display & back-lit OLED display. And keep it close, always, with the handy lanyard attachment.