Equipment essential for skittles (3)
I believe the answer is:
kit
'equipment' is the definition.
(kit is a kind of equipment)
'essential for skittles' is the wordplay.
'essential for' indicates the answer is hidden within the clue (I've seen this in other clues).
'KIT' is hidden within 'skittles'.
(Other definitions for kit that I've seen before include "Set - uniform - gear" , "Specialised clothing or set of parts for assembly" , "Old song 'Pack up your troubles in your old . . . bag'" , "Set of parts sold to be assembled" , "In strip" .)