The back of your TRMNL device has an on/off switch, USB-C input, and multi functional "boot" button.
The boot button does 2 things by default:
Skip to the next screen in your playlist (click)
Reset WiFi credentials (hold for 5 seconds)
But you can program a 3rd function, attached to a "double-click" of this button, with any of the following behaviors.
Identify
Triggers a simple identification screen to help you determine which device is which.
This is helpful for customers with multiple devices who may not give them descriptive names, or who have their devices in the same room with a similar case color.
Sleep
Puts your device to sleep for 8 hours. In the future you may be able to customize this sleep period length.
Add WiFi
Instructs your device's firmware to activate the "TRMNL" WiFi portal so that you can connect to a new network, without resetting your existing credentials.
Restart Playlist
Begins showing content from your Playlist at the top/first position. Think of this as an enhancement to the single-click "skip" feature, as it skips multiple screens all at once.
Rewind
Goes back to the previously viewed screen. Helpful if you noticed something interesting just as your TRMNL device began showing new content.
Send to me
Sends yourself an email with the latest (current) device screen content. Helpful if you want to save/bookmark something for later but don't want to search for it in your Playlist history.