Screen finally put between hot drink and letters for protection (5,4)
I believe the answer is:
chain mail
'protection' is the definition.
(chain mail is a kind of protection)
'screen finally put between hot drink and letters' is the wordplay.
'finally' says to take the final letters.
'put between' is an insertion indicator.
'hot drink' becomes 'chai' (I've seen this in another clue).
'and' means one lot of letters go next to another.
'letters' becomes 'mail' (letters sent in the post or mail).
The last letter of 'screen' is 'n'.
'chai'+'mail'='chaimail'
'n' put within 'chaimail' is 'CHAIN-MAIL'.
'for' is the link.
(Other definitions for chain mail that I've seen before include "defensive link-up" , "Armour with tiny metal rings" , "Protective clothing" , "guard" , "Type of armour" .)