Concept
It gives you information about callers who are out of your address books such as marketers and spam callers.
The design
WiFi or mobile data interface is quite simple and intuitive.
Function
It can also block unwanted call blocks, it is quite efficient to identify unwanted calls and finally match names and numbers.
Usefull
Trucller works first and most importantly as a super-powerful caller ID app. This is a usefull for me if you are disturbed by unknown numbers, then you should use this app once.