This app uses sensors in your Apply Watch to detect your hand movements, and makes you Apple Watch buzz when your keep your hand near your mouth for more than 1.5 second, and it continues to buzz until you remove your hand. This will make you aware that you are biting your nails, and help you stop it.

The app can be set up to work with any of the orientations of the Apple Watch, so you can practice with both hands, one at a time.

The data never leaves your devices.