In short: the number of devices it works with.
The GPS Receiver brings GPS capability to your Apple iPad/iPod touch/iPhone, Android phones and tablets, Blackberry phones, Windows devices and laptops running Windows, OS X or Linux. If you have several phones/tablets/laptops in your household, and you’re looking for one GPS to work with them all, the GPS Receiver is an excellent choice:
The GPS Receiver is completely portable
Slip the GPS Receiver into the included non-slip pad and use it for navigation in a car or on a boat. When you get to your destination, insert the adjustable armband and tie the GPS Receiver around your arm or the shoulder strap on your backpack.
The GPS Receiver has a built in rechargeable battery
The battery powers the GPS for up to 8.5 hours of continuous use. The GPS Receiver does not use battery power from the device it supplies the GPS signal to, so you won’ t drain your phone/iPod or iPad battery.
The GPS Receiver works with a huge number of apps
Most every app for the iPod touch/iPad/iPhone will work. The same is true for Android, Blackberry and Windows.
The GPS Receiver turns your iPod touch, iPad or iPhone into a global navigation device
When traveling in different countries, use the XGPS150 with local navigation apps containing local maps. No need to rent or buy another device for car navigation.