Useful devices for some of the flat chested (7)
I believe the answer is:
latches
'useful devices' is the definition.
'latches' can be an answer for 'devices' (latch is a kind of device). I'm unsure of the 'useful' bit.
'some of the flat chested' is the wordplay.
'some of' indicates the answer is hidden within the clue.
'LATCHES' can be found hidden inside 'flat chested'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for latches that I've seen before include "Door catches" , "locks" .)