htc m7

Hey Guys, totally New here. Just wanted to know what phone this is. It says HTC m8 but its definitely not that as you can see the back design of it. But If this one is full metal, like the M7 and has features like the m8, I am totally buying it. Please guys help out. What phone is this?

So my sister has an android htc one (M7) and i broke my phone so im going to use hers but she forgot the passcode and she wants to delete all of her personal information/details from the phone... How can we get into the phone and factory rest... PLEASE HELP