Apple includes excellent safety features on all its Apple Watch models, but there’s one that's exclusive to the new Apple Watch Ultra: the siren.

The siren is designed to draw attention to yourself if you’re ever injured or lost when exploring. To do that, Apple included a second speaker on the Ultra that can emit an 86db sound with a range of up to 600 feet. When activated, the siren switches between two sound patterns that sound similar to distress and well-known SOS signals.

Once you’ve turned the siren on, your watch screen will show a red border and a call button so you can contact emergency services. You’ll also see your remaining battery percentage. According to Apple, the siren can last for several hours — though that obviously depends on how much charge you have left when you turn the siren on.

There are multiple ways to access the siren from your watch. Here’s how to get started.

From the app grid / list

Like the new Depth app and the Compass app, the siren has its own app accessible from the main app grid or list, depending on how you’ve organized your apps.

• Press the digital crown to access the grid or list.
• From the grid, locate and tap the Siren app icon. It’s red with a white bullhorn in the center.
• In the list format, your apps are listed alphabetically. Scroll down and tap Siren.
• Tap the Play button to start the siren. To stop it, tap the same button again.

From the emergency menu

• Hold down the side button until the Emergency menu comes up. You should feel a haptic buzz.
• The Siren slider will be at the top. Move the slider from left to right to activate.

From the Action button

The siren can also be activated by pressing and holding down the Action button for a few seconds. (You can find a more in-depth Action button how-to here.) However, to do that, you’ll first need to enable this feature in the Action button settings.

On the watch:

• Open the Settings app.
• Scroll down to Action Button menu.
• Scroll all the way down to Siren.
• Tap the Hold to Turn On toggle to enable.

On the iPhone:

• Open the Watch app on your iPhone.
• On the My Watch tab, scroll down to the Action Button menu.
• Scroll all the way down to Siren.
• Tap the Hold to Turn On toggle to enable.

Keep in mind that, when you use the siren, the actual loudness may be impacted by your environment. For example, it’ll sound much louder if you’re in an open field or indoor environment than if you’re in a dense forest or surrounded by rocks.

The volume will also gradually increase, so you’ll have time to make sure the watch is further away from your face before it reaches full volume.

Lastly, if you’re worried about battery life, you can always enable low-power mode to extend the Ultra’s battery life.