Note: This app is no longer developed, https://f-droid.org/packages/pl.lebihan.network/ is a fork that continues development. Simply a shortcut to the activity that you get when you type *#*#INFO#*#* in the dialer. It allows you to choose different radio modes and see general info. In particular you can choose WCDMA only, which could improve battery life if your phone is in a weak 3G area and tries to find a 2G signal all the time. The PRL choices only apply to operators that keep a PRL list.