Gym equipment bays (6)
I believe the answer is:
horses
This clue is a double definition.
'gym equipment' is the first definition.
(horse can mean an apparatus used in gymnastics)
'bays' is the second definition.
(bay is a type of horse)
(Other definitions for horses that I've seen before include "Domesticated animals" , "Eg, stallions" , "''If wishes were . . . . . ., beggars would ride''" , "Hoofed mammals (which go with 19 4)" , "Equine beasts" .)