Track the distance between turn buoys easily! This app makes an audible sound every time your boat travels 134.5 FT so you can focus on piloting. How it works: Press the "Start" button to begin tracking your speed and distance. Once your boat reaches 20 MPH, the distance tracker will begin running. Your selected sound notifier will then begin notifying you at 134.5 FT intervals until your boat slows below 20 MPH or the "Stop" button is pressed. Note: Requires your devices GPS location to display speed and distance. Features: -Simple To Use -5 Preset Sounds -Volume Adjustment Slider -Speed in MPH -Integrated Map Shows Your Location