Easy to use: this finger pulse oximeter designed with one button control which makes measurement more convenient and easier, users just need to put one of his fingers into the fingertip photoelectric sensor for measurement, then the screen will directly show the result clearly Auto shutdown: the oxygen level monitor automatically powers off after 10 seconds of inactivity Accurate and fast: our oxygen blood monitor can accurately determine your spo2 blood oxygen saturation levels in 10 seconds and oled display make this finger oxygen monitors very easy to read 2 aaa batteries power supply design: 2 aaa batteries power supply, you can also use the batteries to supply power at any time anywhere, which is convenient and fast, this oxygen level monitor are very light and small size, low power consumption and convenient in carrying, also it comes with a detachable lanyard which can measure your oxygen saturation anywhere You will get: 1 fingertip pulse oximeter, 2 aaa batteries, 1 lanyard, 1 user manual