It’s officially a semi-automatic telegraph key. Unofficially it’s called a “bug”. One sends Morse code with it.
This helped me avoid college loans.
In a few minutes I was back to about 20 words per minute, which was the speed used for the licensing exams.
I find it yet another example of me being a high tech Luddite. I spend all day working on LTE wireless networks, yet the 150+ year old Morse code and century old “bugs” are not strangers.
If you’re interested in this stuff, check out http://radiomarine.org/