Delivering oxygen through a two-pronged tube secured in place by wrapping the tubing behind the ears is called a

Nasal Cannula

Explanation:

The correct term for this medical instrument is Nasal Cannula. The short explanation is that it is a tube connected to an oxygen tank with two rubber tubes that go just inside the nose to administor oxygen for patients in need of it. If you need to see a picture, simply look up Nasal Cannula in your search engine.

I hope this helps! Have a lovely day.