Doctor, that is manufacturer's last appliance (5)
I believe the answer is:
drier
'appliance' is the definition.
(I know that drier is a type of appliance)
'doctor that is manufacturer's last' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'last' says to take the final letters.
The final letter of 'manufacturer' is 'r'.
'dr'+'ie'+'r'='DRIER'
(Other definitions for drier that I've seen before include "More arid" , "More withered" , "Laundry machine" , "getting less rainfall" , "Appliance to remove moisture" .)