Nanu app useing free call.This app I am useing only 3day.nanu app for free internet calling any mobile number .This app very popular app for free calling. I am download this app affter 3 day and I am call my friend and other.i am total 24 call nanu app.this app calling useing so you must be needed internet high speed.i mean 3g network is batter than 2g network.nanu app you frist download your android phone and you need 1 mobile number for registetion nanu app.you registetion compleat and you call your friend. This app call voice quality is good.so you download this app and free call now.