Reliance jio is the 4G sim. I think that it is necessary for digital India. it offers with free internet, free voice calls, free Sms. at first the offer was till 31st December 2016 but now it has been shifted to 31st march 2017. customer service seems to be very responsible.to get jio sim you just have to download my jio app from your 4g phone and then you will get bar code and after your bar code will generate then you can easily get jio sim from your nearby shops easily. I think this is the best offer till now.