They won't get tight if stripped (4,3,5)
I believe the answer is:
nuts and bolts
'they' is the definition.
Both the definition and answer are plural nouns.
Perhaps you can see an association between them that I don't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for nuts and bolts that I've seen before include "Carries out hit-and-run attack" , "Fastening equipment" , "Basic essentials (colloq.)" , "DDessentials of the ironmonger's trade?" , "brass tacks?" .)