Remarkably rare find that is out of our range (8)
I believe the answer is:
infrared
'is out of our range' is the definition.
(out of the range of human vision)
'remarkably rare find' is the wordplay.
'remarkably' is an anagram indicator (I've seen this in other clues).
'rare'+'find'='rarefind'
'rarefind' with letters rearranged gives 'INFRARED'.
'that' is the link.
(Other definitions for infrared that I've seen before include "(Of radiation) with a longer wavelength than light" , "Fan drier (anag) - type of radiation" , "Radiation from heated objects" , "Sort of light" , "heat" .)