i think yella is refering to the sheffield fine adjuster which is a popular tool among many FIY mechanics. it has a variety of uses including the freeing up of stuck starters , brake drum removal, battery terminal fitting,door catches adjustment, and body panel aligement. unfortuatly it cannot be use to fix bad spelling except in certain circumstances.
if any other member would like to add there own prefered use for this wonder tool i'm sure we would all love to share .
my own favorite is its use as a replacment key to allow entry to vehicle when you have lost yours.