CrApp
It's a real shame because the Raylex Pen is excellent and this is the first time my nails have gone without being bitten in 20+ years.

This app supports users in breaking the nail-biting habit. It provides reminders to apply a specific product, offers helpful tips, and reinforces the positive outcomes of quitting. The goal is to help users feel supported and achieve success in overcoming this behavior.
2.0.8
February 10, 2016
This app has been updated by Apple to display the Apple Watch app icon. - Google Analytics - minor copy changes - iPad compatible
MoreNo, Raylex is ad-free, allowing for an uninterrupted user experience focused on habit breaking.
Raylex is available for free, making it accessible to anyone seeking to quit nail biting.
Raylex is designed for iOS devices, including iPhone and iPad.
The latest version of Raylex is 2.0.8, last updated on February 10, 2016. Updates focus on improving the habit-breaking support.
Raylex has an age rating of 12+, making it suitable for teenagers and adults looking to break the nail-biting habit.
Based on its rating of 5.0 stars, users likely appreciate the supportive nature of Raylex in helping them overcome nail biting.
The app suggests that using it with the Raylex pen can lead to successfully kicking the habit after approximately 18 days.