Rarely producing new models (6)
I believe the answer is:
seldom
'rarely' is the definition.
(I know that rarely can be written as seldom)
'new models' is the wordplay.
'new' indicates anagramming the letters.
'models' anagrammed gives 'SELDOM'.
'producing' acts as a link.
(Other definitions for seldom that I've seen before include "Not 21" , "Models (anag)" , "Infrequent" , "Once in a blue moon" , "Only occasionally" .)