I have buy redmi 3s prime in october 2016.its battery backup is amazing. And it have full secure phone so if you format this phone please remember your mi user id.
If you not enter your id then you have not comleted format. And then you call to Mi custer care.
It have 3gb ram and 32gb internal. And its a hybride sim.
If insert memory cad then you insert only 1 sim and if you insert 2 sim then you cant insert memory card
Over all amazing phone in this price.