Device on a duct (5)
I believe the answer is:
valve
(Other definitions for valve that I've seen before include "Flow regulator" , "Something to regulate flow" , "Device to regulate flow" , "Part of brass instrument" , "Flow-controlling device" .)
I believe the answer is:
valve
(Other definitions for valve that I've seen before include "Flow regulator" , "Something to regulate flow" , "Device to regulate flow" , "Part of brass instrument" , "Flow-controlling device" .)