A height measurement ruler.
You can measure the height of mountains highly accurate (accuracy ± 0.5m) without actual ruler.
You can measure the height of the building highly accurate (accuracy ± 0.5m) without actual ruler.
You can easily learn the barometric pressure of the current location.
Warning: This application is designed for iPhone 6, iPhone 6 Plus and iPad Air 2 , other devices can not be used, make sure carefully before downloading.