Styling product (3)
(Other definitions for hair gel that I've seen before include "This used to set" , "something for shock?" , "Fixer of locks" , "Application for styling job" , "style fixer" .)
'styling product' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gel that I've seen before include "Semi-solid" , "Upstage" , "well-spoken deb?" , "Hair cosmetic" , "Become jelly-like" .)