Small, more streamlined, gardening equipment (8)
I believe the answer is:
strimmer
'gardening equipment' is the definition.
'small more streamlined' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'more streamlined' becomes 'trimmer'.
's'+'trimmer'='STRIMMER'
(Other definitions for strimmer that I've seen before include "Hand-held grass cutter" , "Garden equipment" , "Machine for cutting grass edges" , "Cutter for rough grass etc" , "Brush cutter" .)