Activates and deactivates Wi-Fi depending on your location, helping you to save battery and consumption of data through your cellular network. It detects automatically the location of known Wi-Fi networks; turns on Wi-Fi when you arrive a place where there is Wi-Fi, and turns it off when you leave. Simply turn start the app once, enable WiFi where you need to and the app will learn over time. It uses network location services only, which are normally provided by Google Apps though there is a solid replacement by NoGapps project. Of course, cellular connectivity itself is a large battery drainer and you'd be better off to leave the phone in Airplane mode when you can.