This might look like a little tube of Chap Stick, but it's not. This is a product called NuScreen HD that is designed to be applied to the screen of your touch sensitive device like a smartphone tablet. The idea is that the slightly slippery and non-greasy product will prevent fingerprints and smudges from getting on your screen.
That would mean a better looking and cleaner device for you to look at. It also means that if you have a device with sensitive information on it for work someone that finds your phone won't be able to use the fingerprints to try to guess your password.
The product promises to not leave a greasy film and to make the screen slippery. The tube looks small, but I bet it will last a very long time. It claims to be tested to work without hurting touchscreen on Apple products and lots more. A tube of the goo will set you back about $20.