Only remaining part of a shoemaker’s equipment (4)
I believe the answer is:
last
I believe this is a double definition.
'only remaining' is the first definition.
(the last thing is the only remaining thing)
'part of a shoemaker's equipment' is the second definition.
(tool used by a cobbler)
(Other definitions for last that I've seen before include "Survive; after all others" , "Ultimate - endure" , "The cobbler's equipment will endure" , "Continue" , "ending a series" .)