Diver's equipment (5)
'diver's equipment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for scuba that I've seen before include "Skin-diver's device" , "Apparatus for divers" , "Skin-diving apparatus" , "breather" , "Device that lets divers breathe under water" .)
(Other definitions for snorkel that I've seen before include "Bent tube for a swimmer's mouth" , "source of inspiration?" , "Diver's breathing tube" , "Diver's air-tube" , "diving equipment?" .)