This sort of stock ticker uses a small metal wheel that continuously rotates from letter to letter, with an electric mechanism to print the letter that's currently in position. That makes it very slow compared to teletypewriters -- you have to wait for the needed letter to come around, rather than just lifting the correct typebar. Teletypewriters also have mechanisms to move a full-width sheet or roll of paper, which makes them larger than the roller that this ticker has to advance its paper tape.
I've had a hard time finding tickers in pictures or videos, but here's one; skip to nearly the end to see it printing.