Regulator device (5)

I believe the answer is:

valve

(Other definitions for valve that I've seen before include "Flow regulator" , "Flow-controlling device" , "Structure with a flap to insure one-way flow of fluid" , "Flow controller" , "Part of brass instrument" .)

I've seen this clue in The Sun.

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.