Tell a friend that your iPhone is dying and they might advise you to turn on low power mode. In fact, once your battery drops to 20%, the iPhone itself will ask you if you want to turn on low power mode.

It’s generally understood that low power mode will extend battery life, but many iPhone users might not know what else it entails. Here is a preview.

Your iphone does less when in low power mode. Your brightness will dim, your phone will automatically lock after 30 seconds, and your connection won’t be 5G unless you start watching a video. A bunch of background processes can also stop temporarily, which you might not even notice. If a new episode of a podcast you’ve subscribed to comes out while you’re in low power mode, it probably won’t automatically download the way it usually does: automatic downloads are paused on LPM. Your apps won’t update on their own either, and your photos won’t automatically upload to the cloud.

As Popular science Explain, you can skip some of these features, like turn the light back on or open your podcast app and manually download new episodes. But if you want your phone to do this for you, you’ll have to turn off LPM and accept that your battery power will drop a bit faster.

As for how to turn it off (or on), the button is under Settings> Battery. Your phone will turn LPM off once your battery is at least 80% powered, but you can always choose to turn LPM back on yourself.

[h/t Popular Science]