Make rep, cryptically, for diving equipment (7)
I believe the answer is:
flipper
'diving equipment' is the definition.
(a diver might wear flippers on their feet)
'make rep cryptically' is the wordplay.
'make' becomes 'flip' (I can't justify this - if you can you should believe this answer much more).
'cryptically' indicates an anagram.
'rep' with letters rearranged gives 'per'.
'flip'+'per'='FLIPPER'
'for' is the link.
(Other definitions for flipper that I've seen before include "Flat broad limb of aquatic animals" , "Before the game, the referee perhaps makes" , "Shoe for swimming" , "Limb used for swimming" , "Seal/turtle limb" .)