Cooler follower (3)
I believe the answer is:
fan
This clue is a double definition.
'cooler' is the first definition.
(something which cools)
'follower' is the second definition.
(fan is a kind of follower)
(Other definitions for fan that I've seen before include "Manually wielded cooling device" , "Cooler; enthusiast" , "Cooling device or disciple of performer" , "Cool - enthusiast" , "Enthusiastic admirer as of pop star" .)