If you use a Windows phone, expect this when Windows 10 update for everyone comes out.You might as well look out for a Windows 10 phone if you are thinking of purchasing one.
What's the deal this feature?
You can use one hand to do everything on your screen.
Windows insider updates pushed out recently came with quit a lot of features and this is one.
Just like the iPhone 5 and 6, Windows 10 users will have to put a two second press to the windows button to use this feature.
Here are screenshots I made with my Windows phone.