Hello guys. The google launced new video calling app its name is Google Duo its HD video calling app I am using this app its quality so good and you can use in 2g/3g and 4G its signal strenth good you can the app in playstore for free its not paid only free you can call a everyone use the app AND the guys download the app and use I am using in 2g to call anyone an its clearly worked and fast call its best for calling you can download and enjoy the Google Duo app and call your freinds and parents and suggest to download Google Duo app