This is an application for 4g volte call function. This app is one of the jio apps. I installed this as it support volte service in any 4g phone. But I found this app not useful for my device as my phone support volte service. Volte is the internally function of my phone. All the layout and design are similar to internal call function. This app may useful old 4g phone which do not have volte feature and by this app we can call over the lte service. Means we can call by internet. Overall this app is useless for the phone which support volte service.