They can open doors for you (5)

I believe the answer is:
knobs
(Another definition for knobs that I've seen is " Rounded projections or protuberances".)
I've seen this clue in the USA Today.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free.
Check out my app
or
learn more
about the Crossword Genius project.