The Popsocket is a plastic circle that attaches to flat phones (or cases) with a sticky, reusable adhesive. They “pop” out twice and look like a small accordion. They're easy to remove too.
The most obvious use of a Popsocket is as an additional grip. This is especially useful for larger smartphones. If you have a tendency to drop your phone a lot, or have smaller hands and find it hard to hold the phone comfortably, a Popsocket fixes that. With a Popsocket, you can more easily hold your device one-handed and browse without issue - it's much more comfortable.
Popsockets make it much easier to take selfies and can act as a stand for your phone when you want to lean back and watch some videos. They even make it easier to keep headphone cords wrapped and tidy.