Flexibility Tracker: Range is an iPhone application designed to help users measure, track, and improve their physical flexibility. It caters to a wide range of users, from beginners to seasoned athletes, providing guidance on various stretching techniques. The app utilizes the phone's camera to measure joint angles and offers a user-friendly interface for logging progress through pictures and data analysis.

Key features include quick and accurate flexibility measurements, progress tracking with visual charts, and motivational elements like flexibility levels and badges. Users can compare their logged pictures to observe improvements over time and categorize measurements based on warm-up ratings. Range is free to download, with a subscription model for continued use after a trial period, making it a valuable tool for anyone looking to enhance their flexibility.