Speedometer and GPS app for both your iPhone and iPad. It displays your current speed and distance. ‣ Need to know where you are? Integrated map shows your location and a tracking "tail" behind you. ! You can use this app on your iPhone 3GS, 4, or 4S as well as on any iPad with 3G. **App will not work properly on iPods and wifi only iPads as they don't have GPS chip (External GPS module is required). ! Please note that as with all GPS apps, continued use of GPS running in the background can dramatically decrease battery life. * If you wonder why gps speedometer may show 3-5 mph (3-8 kmh) less than a car's speedometer, you can take a look here: http://goo.gl/wtLvT (tomtom's discussion thread). ** And here is an amazing article http://goo.gl/p5zfMi explaining why GPS might show you 80ft (or -80!) altitude when you are laying on the beach. Don't throw the app or iPhone away just because of that! :) Let us use the article's last sentence here: "Those who use GPS altitude to aid in landing their small plane should have their insurance policies paid up at all times".