Jio Phone is a dialpad device from reliance. It is a locked device which means only jio sims can be used on this device and the sim card given with it can only be used in jio phone not on any other phone.
I have 3 jio phones in my house. One was very laggy and slow. Rest two were decent. You can do a lot of things on this phone. Literally you can run WhatsApp and Facebook. Well playing games is my favourite activity.
One major problem with the phones is that their battery swells up very often and then you will have to replace the battery that will cost 200 rupees.
Overall the plans you get along with this device are very attractive. I have one that gives 2 years of free calls and 1 GB data per month.