Easy to use: this finger pulse oximeter designed with one button control which makes measurement more convenient and easier.This Product Is for Sports or Aviation Use Only and Not for Medical Use Auto shutdown: the item automatically powers off after 10 seconds of inactivity Fast and Easy: This item provides readings in just 10 seconds, with an OLED display that makes results simple 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 item are very light and small size, low power consumption and convenient in carrying, also it comes with a detachable lanyard